Slush - 2% commission = around 50 BTC per day, whereas paying for a dedicated server only costs around 100 BTC per MONTH.
[Tycho] - 3% commission, but he supports long polling and you do have the option of being paid immediately instead of waiting for 120 confirmations.
Geebus - 0% commission + long polling support - Really everyone should be on here pushing the average work time down and making it the best of the three pools.

Is there something I'm missing?