Lots of previous posts on this. If you're willing to work hard at improving, the tools are all there!
http://www.chess.com/forum/search?keyword=diamond+benefits
Oh, and here's a link that lists all the perks:
http://www.chess.com/membership?c=navbar
Hello Chess.com members! I want to know the benefits of a diamond membership and the stuffs that can be done to improve ones Chess as I'm thinking of buying one. Thanks