It is a good app for downloading any type of content specially for downloading youtbe videos. It allows to download youtube videos in HD even in 1080 p also. Basically IT IS A GOOD App.
Now this app is also illegal because youtube not allow to download any video from its website.You may also noticed that the app is not on the playstore because of its illegal work.
BUT his app is good bacause of its designing or downloading.you can see all trending topics in front page of this app.
SO, it is a good app .also illegal
THANK YOU GUYS