Firstly, please note, the score I gave is for the current (i.e. 3.0.1) version.

Stylish (up to 3.0.1) was a wonderful thing. You could style (that is, inject CSS into) websites (with various, like regexp, methods to define which urls to style), and, which is super important for me, you could style XUL (UI) in Firefox. Some may say, this can already in Firefox be achieved with userStyle/userChrome.css files in your profile dir, but stylish had a few advantages over those:
* you could split the rules into multiple parts and independently enable/disable those parts DYNAMICALLY while the browser is running (without even needing to reload the page or restart the browser)
* you could test rules dynamically and change them until you have what you want, again without restarting the browser or reloading the page
* you had a centralized system (userstyles.org) from which you can download rule sets and it's ultra simple (you don't even need to know anything about CSS)

Now, about stylish 3.0.1.
I don't really know the full set of changes it made. Some, or most of the advantages listed above might still hold. I don't know, because I have downgraded it immediately after restarting Firefox (after an upgrade) showed me the damage done.
What damage and why did I downgrade? Well, it's simple. The problem is XUL STYLING IS REMOVED.
XUL (Firefox UI) styling is what I mostly use stylish for, so without it it's basically useless to me.
Now, I know Mozilla has decided, against the wishes of many, to remove the ability to style XUL within the new web extensions API, which will be the only API for addons in Firefox 57 and beyond. And I know stylish developers wanted it to work in 57. But stylish 3.0.1 is advertised to work with versions from 48 to 57. So I would imagine, it should allow for XUL styling in 48-56 and only ignore it for 57. I think this is possible, as stylish could be a hybrid legacy/web extension addon like there are some.
Also, another thing is that stylish 3.0.1 doesn't tell you in any way on update "hey, some of your styles were disabled because of blah blah, here's the list: blah blah; if you want those to work, please downgrade". Nope, there's no such info, not even a "screw you". And I know it's possible to even display a new tab with info upon update, since NoScript does that for example.
So, in summary, my issues (could be possibly that there are more):
* My XUL styles stopped working, Firefox greeted me with it's default, (in my opinion) ugly, cramped and borderline unusable theme. It's possible all my scripts stopped working (including those for pages), but I didn't even check, as lack of XUL styling makes this version unusable for me.
* There was no message informing what happened and what I can do.

Here's what the stylish developers could to in order to fix those issues and increase my opinion:
* Include support for XUL styling fro Firefox pre-57, possibly by making a hybrid extension.
* If that's not acceptable, maybe fork stylish, with one fork for 57+ and another for pre-57 with XUL styling support, with both maintained.
* If you want to keep not supporting XUL styling:
* Stop advertising this extension as working with pre-57, because it's a lie - currently it's crippled in pre-56 to fit the requirements of 57+.
* Please note so clearly in the release notes, so one can click on release notes in updates in about:addons and see this update is unacceptable without wasting time by updating, figuring out what happened and downgrading. 99.9% of users won't read your website or github before updating; probably also nearly no one will read release notes, most people will get an auto-update, but some will and so such note would be helpfull.
* Also, please show a page upon update explaining what happened (some of your styles were blocked because X and the list of them is Y), what can you do to resolve this (e.g. downgrade) if something (e.g. blocking of some styles because of X). This will be very beneficial to those with problematic update, because they will: a) know what happened; b) know how to fix; c) be able to evaluate wether they can accept the update or have to downgrade. And it will probably for many significantly reduce wasted time (if an addon malfunctions due to an update, I can sometimes waste a few hours trying to figure out what happened before I find the culprit and downgrade, because upgrades are often done in bulk and you don't know which addon to blame, or is it maybe the combination of addons that causes this, or if it's a firefox version-addon version combo, or just firefox, etc etc. and also the issue can manifest itself weeks after the update, making the investigation even harder).
* I had something else to list, but I''m so furious and have been editing this comment for an hour, that I forgot. Sorry.

Anyway, if you ignore AMO comments, please let me know, so I can nag you on github or whatever.

AND NOW SOME NOTES TO USERS AFFECTED BY THIS TRAGEDY:
1. You can downgrade to the previous version, 2.1.1. On the addon page on AMO, there's a sidebar on the left with "More information". There's a link there "See all versions". Click it and in the opened page, find the version you want and click on "Add to Firefox".
2. In my case at least, after downgrading my styles were there. But in case you're afraid of loosing your data, best to backup the profile directory, or at least the stylish.sqlite file inside of it - it's an sqlite database file, which contains a table of all your styles (both enabled and disabled) with their ids, names, and content. If you think you lost the data after an upgrade and don't have a backup of this file, then don't panic and:
* Close Firefox.
* Copy stylish.sqlite somewhere.
* Start Firefox, downgrade stylish, restart, check if styles are present.
* If not, check if the database file (stylish.sqlite) you copied contains the style data. You can do that by loading the file with sqlite3 tool and issuing "select * from styles;". This can be done with "echo 'select * from styles;' | sqlite3 stylish.sqlite" on unix. If you have trouble, send me this file in an email and I'll check it. Don't worry, it doesn't contain any sensitive data. If the data is present, you can just create styles you want and copy-paste the css code into them.

People hate changes, but this extension is a MUST HAVE for me. Can't stand this guys acting like little children because the new version 3.0, learn the new way, is not that difficult.
Seriously, this first world problems are ridiculous...

avoid version 3+

CALM DOWN FOLKS, THERE'S A FIX FOR THIS

Go to "See all versions" It's in the "More information" tab on the main addon page. (Use ctrl+F if you can't find it)

Then install Version 2.1.1
Then restart Firefox

Your styles should all be back.

Congratulations.
You just managed to anger ALL the fanbase of this extension. If I didn't have the backup for my custom made style (and I like to tinker a lit, so I've a huge lot of style -most experimental) you woul'd have removed those too.
Moreover, not only you changed who the hell know what about the saved style, you managed to change the write mode of the theme too.
why in the nine hell I've to put externally of the code the site upon this extention work while until now it was internal?
why should I bother to rewrite all my style if you will just change the code again in the fture?
why now the extension connect to userstyle.org to get miniatures?
why there isn't an option to remove the miniature under the button to let me read the da.m.ned full name of the style?
why there isnt' a single option for the extension, by the way?
why shouldn't I put on an older version and lock up the update for this extension?
why shouldn't I chage with stylus since you just copied the extension and called it a day?

And, finally, why should we have again faith in you since this pure and unmitigated disaster? You managed to not only destroy all the hard work you put in the extension until now, you managed to destroy the will to make donation for the extention too.

waiting for your anserw.

觉得自己的旧样式消失了的，点击about this version就可以找回它们
if you think you styles was delete，click “about this version” and you can find it back

不过旧有的很多样式在新版本下都不可用了啊

lost all my previous styles. found it very confusing to try and recover. tried installing new styles installed 2 only 1 showed on installed styles never showed up on my home page then the #1 disappeared off the stylish icon on bar. didn't appreciate not being given the option of installing this on my own. should this practice continue will be switching to google chrome for my browser. have returned to older version of stylish. new version is totally useless to me.

Like most of the other users i also lost all of my styles.

I could recover the old styles. The are stored in the file stylish.sqlite located in the used profile folder. I suppose Stylish is using this file on Windows too.

After copying the file stylish.sqlite to another folder - this prevents overwriting by Stylish and really loosing all styles - you can use DB Browser for SQLite (http://sqlitebrowser.org/) to read the file. Using Debian or Ubuntu you can install the package sqlitebrowser.

Open the file stylish.sqlite and recover the code of the styles:
1. start DB Browser for SQLite
2. open the file stylish.sqlite
3. click at the tab "Browse Data"
4. select the table "styles"
5. click the a cell in the column "code"
6. copy the code shown in the windows at the right top

Good luck...

Guys you can rollback to the previous 2.1.1 version here which will enable your custom styles again...

Just remember to set Automatic Updates for Stylish to "Off' within the FF Addons page.

https://addons.mozilla.org/en-US/firefox/addon/stylish/versions/2.1.1

The new update deleted all my styles, and the stylish addon stopped working all together. Switching to Stylus. https://add0n.com/stylus.html

NOW A PIECE OF JUNK!!!

used to work perfectly fine and used it for many sites. now after this update:

it deleted ALL my styles,

WONT let me re download them because all the install buttons for styles redirect to here!! HAPPY NOW WITH YOUR 1 STAR?!

pressing the mini button in the menu bar only creates a white arrow underneath with nothing else.

even the options button in addons only brings up an unnamed empty tab!

CONSTANTLY tells me to install it, yet i have it on my menu bar.

THANKS A LOT!!

Last update broke my themes for some of the websites I use the most, so I'm not happy. Please fix it

Thank you for nothing, the silent deletion of my custom themes was really a nice surprise.

EDIT: PEOPLE, REVERT TO VERSION 2.1.1 THEN EXPORT YOUR FILES TO STYLUS. MUCH BETTER.

I feel grateful with the devs right now, thanks to this garbage update I'm heading into a better direction.

Уже лучше, но исправьте зависание стилей: когда обновляешь страницу, она часто загружается в обычном стиле, и ничего не работает, поставленные стили не применяются, это очень раздражает.

Всё сломали. Верните как было!

Just a scheme that, with all the criticism you got, you've not reverted back (or forward but ...) with no MAIN trouble as everyone is pointing on !!!!

RIP

Delete button is next to edit button with no confirmation!

It's a pity that you decided to make such big changes without letting us decide if we want to write our own styles and keep the ones we already had, or if we prefer to pick one of the new ones. You totally changed how the extension works, therefore that's not an update, you should instead create a new extension when you make such big changes.

You just deleted all my styles without asking me first if I wanted to save them.

Shame on you, I'm uninstalling as many others.

PS: Newer versions of Firefox are not compatible with older versions of Stylish. Goodbye, Stylish. It was nice and everything but that's all.

Very good and nice to use.

Sorry to say that but the new version 3.0.1 is a crap. It lost all my styles. The interface is hard to understand.

Get back the old interface!

userChrome styles do not work anymore!!! As a workaround I have to use the userChrome.css file which is a annoying for multiple styles. (And the new design takes to much space.)

Unfortunately it does not work I've increased my craziness to Firefox