I'm a club-level player and Chess book cover artist for Gambit publications. I just want to list my own views on chesscube so far:
1. GUI. One of the best I've used yet on the internet. The seek graph reminds me a lot of Dasher, and the overall design of the chess board interface is quite pleasing.
2. Love the game history and rating graph.
3. The avatar and profile options are a great start.
1. Not being able to turn off specific sound effects. I only want to hear the piece movement sound when I finish moving it to a new square, not when I change my mind and move it back to its original square. The extra movement sound from doing that makes me think I accidentally made a move when I didn't.
2. Perhaps I missed the option, but I'd like to see a settings option to disable all chat during a game. I know you can ignore spectators, but it would be nice to disable participant chat too, and before the game even starts.
3. Profiles tabs should also show web site links if the user puts one in. So far, I can only see name and email address.