Unlike other reviews, I have not run into spam ads/popups. You just have to use the right ad blocker.

Works great for getting around Youtube's recently changed (some time between Dec'19 - Feb '20) format of not allowing other local downloaders to detect any audio formats or video formats besides webm.
Also downloads quickly, with a bunch of options for trimming, volume, bass, treble, speed, album art like the description says (haven't tested it all though).

However, it must open a new tab to a website that pastes the link and then has option only for 128 or 356kbps. I do not see variable bitrate available.
Anyway, it works fairly decent for most basic purposes and editing. Though I wish it had the variable bitrate, and was a local app than a site.