I've tested this in Chromium and in Firefox. In Firefox, it is currently Experimental but seems to work okay.
It won't work with Firefox ESR, only Firefox release channel. It would be much easier for me and probably many others who use Firefox ESR in Linux; no need to install two different versions of Firefox.

Maybe I need to change my workflow, but one feature of BitWarden I like is the ability to pop-out the window of the extension. This comes in handy when you need to toggle between the password manager and the page open in the browser or in a browser on a different monitor. With Proton Pass, better not get half-way through creating an alias or login and click outside the extension... or you have to start over.

So good so far and so happy you have added this. Now I can get rid of my old Norton Password Manager - albeit no import option for this manager. So only 4 stars since cannot import from that.

I installed both the Android app and the Firefox extension yesterday, migrating my data from Bitwarden (which I am keeping for the time being). Both products are functional and well designed, but I am giving "only" four stars because I expect them to evolve rapidly and become a truly exceptional password manager, as it happened with all Proton products so far.
A fully satisfied Proton Unlimited subscriber ;-)

Was using BitWarden, which is fantastic. But since Proton Pass came out, I wanted to try it since I already switched to use Proton Mail and Calendar. I like the idea of having "all my things in one place" (as long as it's a good place).
Both the app and the extension look good and simple. Exporting json from BW into PP had no issues and I have already used it on a couple of sites. I give 4 stars since just comes out (at least publicly) and devs don't get high on success and keep improving it :P but I can recommend!

I can confirm, that login is not detected on some sites. I can generate password at the signing up on site, but it is not saved by the extension..
My example is https://dotacjenaokna.pl/logowanie-strefa-dilera/

It would be nice if, when I create a new login manually, on the button instead of "Create login" there was simply "Save"

Great features overall, but seriously needs a form fill shortcut like Bitwarden has.

Great addition. While it is at experimental level, I am enjoying the basic functionalities. Keep up the great work!