They are even cheaper than IB @ 0.50per contract. If the Thinkorswim Ameritrade merger create something undesired, I'll consider Trade Monster.
Have you ever looked at Options House? If you're doing small size, there are probably better places. But OH charges a flat $9.99 fee no matter how many contracts you put in a single trade. It's especially beneficial if you trade a lot of multi-leg trades.
Pretty friendly customer service, however i would prefer TOS/IB as the commissions are much better and also I like a desktop platform. Browser based systems are cool but Desktop versions have more power. Though I have to admit that I like their streaming quotes on the platform and it is a pretty nice looking flash app