[ajmargarine]

You're playing for set value, and you didn't hit your set. Calling is fine on the flop in case you are up against an AK continuation bet. When villian calls the turn bet, you're beat by a bigger pp almost always, and have to fold the river. Turn check may have been in order. Let's him draw for free if he's not paired, but you have redraws to a straight if he is paired. This tradeoff manages the pot-size and is slightly better than betting the turn, JMO.