I pay for a Diamond membership though I don't need or use all the features, to avoid the cheap political appearance of chess.com crownyism.
what do you think about each membership?

I went diamond because I wanted unlimited access to the ChessMentor. Sure I try to keep up with the videos, and I think the videos are generally first rate, but let's face it: there are lots of places to watch videos. The ChessMentor though is unique to chess.com. Notice you haven't tried the CM yet so I'll give you the link to 15 free courses so you can.
http://www.chess.com/blog/webmaster/free-chess-mentor-courses
hi everyone i just wanna know whether i should choose a gold,platinum or diamond membership>i want to choose gold is it worth it?:)