I play on Stars for cash game, but will likely move away soon as it continues to get much tougher each year. The software on Stars is far superior to any other site though apart from FT.

For mtts and building a roll, many of the smaller sites/skins offer better freerolls and money-added mtts than Stars and also smaller fields in micro mtts, which results in shorter tournaments (great if you have to get up for work). You won't get the big first prizes away from Stars, but you will get lower variance.