Rated 5 out of 5 stars

Great add-on. Many more options than most of the others I've tried, and for this reason it was a little daunting at first. But well worth the time to learn how to use it. Can download and convert to an impressive number of formats.

I've only had one issue. For high quality MP4s it's supposed to merge audio and video after the download's complete, but it's not working for some reason (5.6.17). I'm using XP (no .NET) with "Hide console window" unticked per the instructions, and a recent version of ffmpeg, so not sure what the problem is.

Would recommend as first choice.

***UPDATE***

I was using FF31 so updated to FF36 and it's working great now. I think part of the problem was my own fault. Sometimes after the download starts I close the browser and just watch the download window. I've got it set to close the download window automatically when the download completes, so after the download finishes and the window closes, the FF process quits and CYS can't run. Duh!

This review is for a previous version of the add-on (5.5.1.1-signed). 

Thanks for the 5 star review!!!

Sorry to hear you are having a problem with CYS. We did receive your email and will be contacting you shortly. BTW, with v5.6.17, you no longer have to unhide the console window in WinXP; ffmpeg should work just fine without .NET framework.