[MrWookie47]

I'll chime in here for a bit, too. I ran some pokerstove numbers for starters. I gave SB a somewhat liberal range: ATo/s, KTs, 98s, T7s, or any set. There might be some other club draws in his range, but that's a start. CO got a random hand. The stove cooked up about 40% equity for us, about 51% for SB, and just under 9% to CO. If we 3bet and fold CO, SB will inherit just about all of his equity, making our 3bet will be taking the worst of it by a significant margin. If he calls, the raise may still be +EV, but I think that my range underestimates the probability of SB having a set here. That c/r in a protected pot is a strong move, indicative of a good hand. A draw might be a little optimistic here, and a player with a VPIP of 25 calling some of those hands in the SB should be discounted somewhat, too.

Now, there is the free card argument, but look at this. If we hit on the turn, the SB betting is a very good thing, especially if CO calls. CO is more likely to call on the turn than on the river after we take a free card, SB bets and allows us to raise after hitting (or being smart and checking). Our implied odds of hitting are much better if we have SB as the aggressor rather than being the aggressor ourselves. This lets us raise (rather than merely bet) when our edge is huge, instead of raising now when our edge is small (or negative, if CO folds).

Put me in the camp for calling rather than 3betting. I don't want to fold CO, and I like our implied odds a lot better if SB is the aggressor (and CO is still around to pay us off).