画質やサイズを選べるのが良いですね^^
ありがとうございます

I have used this addon over the past year nearly on a daily basis due to my work in video production. Not only is it easy to use but it also never failed me.
I have recommended this addon to everyone I know who should know about it but more so, have established it for everyone in our company for over 375 people.
No one has ever had any problem with this addon.
Therefore, I can only recommend the use, the ease of implementation and accurate result delivey for anyone. Ever Firefox user should have it automatically installed.
A big Thank You to the Author.

Use it 'almost' daily. Works on most sites very well and quickly. Would hate to lose it!

It is good, Downloads the video in various format without any ussues

2022_1011: Giving 5 stars now. The developer has kept up with YT changes over the years, and it is great to be able to count on this extension working. Generally, 720p videos download almost instantly, and 1080p videos take a bit more time (from a few minutes to more than a day), but the videos always come through.

2 Years ago: It works great and fast, but only after the first few attempts to use it - even when closing and reopening the browser. My initial experience: 1) At first, it would give a message saying to wait 5-25 minutes for processing. 2) After waiting a bit, it would show that it was processing the video, which it did to 100 percent. 3) It would then say it was transcoding it, and it would remain on that screen for a LONG time, more than half an hour. 4) When I finally got tired of waiting and decided to refresh the browser page, it came right up with a dialog box asking for where to put the finished file - which I would not have known about at all if I had not refreshed the browser. It did the same four steps above for several videos in a row, and then on a subsequent video (I think it was number four in my testing), it finally went straight from step 1) to step 4) in a split-second, and then all videos I tested after that did the same - immediate download upon requesting it. It was as though the add-on had to learn who I was before it would actually work quickly and not make me refresh the browser just to get to the next step. I have not tried it yet today - a different day, with a newly-launched browser - to see if it will continue to react quickly or if I have to go through steps 1) to 4) all over again.

Original:
This is an excellent add on! I've been using it for years. It is effortless to use, updates easily, and I wouldn't be without this tool, especially in this day and age when things are disappearing from Youtube left and right if they don't follow the party line.

6/23/21 Still the best add-on I have! Highly recommend!

11/02/22
This continues to be an app without peer - always works well, and if they are working out the glitches created by Youtube, the new download button on the tool bar still makes the download function available. Couldn't be happier to give a 5 star review!

Very easy to use, Thanks very much!

Very good and handy add on. REally easy to download

Love this grabber

Love this add-on. It actually does what it says it does. Downloads are fast and easy to do. Thank you.

I've tried many of these downloaders. This one is by far the most reliable and easy to use. A very small donation to help them stay up to date (which, unlike the others, they do) is all they ask for their work. Don't waste your time with the others. This one is great!

Absolutely helpful – I've chosen the extended version (available with a donation) and highly recommend it! Update: developer actively supports this extension even when necessary very fast – worth paying for it every cent.

works perfect for me with video.

One of the very few downloaders that actually work. And not trying to trick you with malware.
And also gives you a fair chance to download popular pieces for free.
And even downloading everything else is available at a fair price ($10).
Dishita is constantly working on it to keep up with YouTube changes.

Works great! I've used others but they eventually quit working. I've never had that problem with this one.

Epic, first thing I add on when I have a new ff install.

very easy to use

Great add-on. Very easy to use and constantly updated to keep up the pace with Youtube changes, Thank

This is an awesome plugin. It has been working well for me for many years. Thank you

This add-on works perfectly well on downloading Youtube videos. I use it to keep videos of my favourites artists and it is great.