Half-Good, download some.

When it's available, it works like a dream, but it often vanishes from YouTube without warning for long periods. I have no idea why.

its a little bit scratchy

The addon doesn't work well with the new YouTube layouts and can't download to 1080p.

I have not used this add-on in quite sometime, now they want money for a Pro version which used to be part of the original add-on.

Pulled the trigger on Pro. I'm on the fence. I get blocked IP a lot. I wish people would give up the ghost on doing this server side and do what another add-on did and just download both files locally and use a client app to encode them. Or just give us the option to download ourselves and I'll do it myself.

Paid PRO version currently doesn't work with Firefox v79.0. Worked perfectly for years prior to a few days ago. Working with Support to try to determine what is causing download process to stall. Will submit updated review when (if?) solution is found.