I used to play on chess.net when they were completely free. When they started charging money, I switched to FICS (freechess.org). I don't know if chess.net has added any new features in the 5 or 6 years since I was there, but I can't think of anything it had when I played there that FICS doesn't also have, but for free.
My standard recommendation is that everyone should play on FICS, unless you're a master or grandmaster, because there won't be enough strong competition on FICS to keep you occupied. In that case, you'll probably have to find a pay site with stronger competition, which probably means ICC, but perhaps chess.net or another site.
--Fromper