Notube basically runs a racket, spies on people and spreads malware.
Edit. Now instead of addressing the issues their employees are policing the comment section. In reality notube pretends videos are Copyrighted when they aren't and does other things to intentionally impede the download. Then they ask you to pay to upgrade to premium so they can promise to stop sabotaging your download. That's a racket. Demanding pay to not cause problems. Many many other issues.