I have bet at Sportsbook and Bodog.
Bodog is better about actually paying you promptly.
Odds are similarly shitty, in that the middle end is WAY too expensive to be profitable.
IMO, if you place an equal bet on both fighters at the same time, it should be such that your loss to the middleman is small, but the sites themselves take way too much.
On the other hand, if you play the stock/forex/options/bond markets in the same manner, the fee is really tiny.
"C'mon Andy, let's go! Go for the single leg!" - BJ Penn
"C'mon everybody, Let's hear it for Josh KosCHECK" - GSP
"Lyoto won all 5 rounds." - Anderson Silva