Hmm...

I guess I was a little misled on the first reading of this hand, let me re-read it...

Ok, we have Aces, and we keep Aces in his range, but AK, AT are the two we are most scared of (AK has us beat and a SD, AT is looking at a straight draw...), how likely is villian to be in this hand with SC in spades or diamonds? Since they are pretty nitty but it is a small sample, I'm not so sure we can rely on it...

But they limped UTG... hmm...

I'm thinking pocket pair, that may have set. You might be in trouble here... but I think with the level (5NL) and the nitty image, you may be better off folding, but me being the casual player I am, I'm likely to shove this. He's only calling a shove with a set. Unless he is lost... IMO... but again, I'm a low hand count casual player... believe the better players over me

If you don't know that history, you can narrow the flush draw chances a bit, likelyhood of him holding diamonds isn't great I don't think, mostly because of the number of them already visible...