Interesting hand. With no read at all on the player, i would probably call, though mind you its a VERY CLOSE decision. You have top two, and are beating alot, but are behind to a a set and KJ. Cant really put him on
(although if i was in the hand, i GUARANTEE you thats what id turn over) Hard to put him on AA or QQ because there was no PF cap, so TT and KJ are your main concerns here id say- of course he may have AQ also.
On the other hand you gotta ask- what was worth raising on the river that was not worth raising on the turn? Some guys like to wait till the river to raise the stone-colds, because the worst conceivable fear in thier mizorly little hearts is that someone will laydown to thier turn raise. The only hands he might do this with are AT if he was trying to slowplay, or A5, if he's a mizor and raised that mess UTG and hit his kicker. I would say that if you are good, he's probably got A5, since i see no reason why he should wait till the river to raise unless the 5 somehow helped him, unless like i said, he was a lil beyotch playing a set or a straight that way, making sure the river was blank before he raised (like, no one card broadway or board pair)
Again, as much of shorthanded is, and i hate to say this, but its pretty read dependent. Lots of mizors in SH, and i mean LOTS like to make marginal river raises for value. I have seen this done with as little as AK in a spot like this, or even AJ, depending on how aggro the guy is. It pays to pay attention to the mizors in SH games- which is one reason i cant understand how xaston can play 4 tables of that damn game- but apparently he's as big or bigger of a winner than myself at those limits, so there aint much i can say about it.
In any case, without any read at all, or rather, without a halfway decently based read that the guy is a mizor, id probably just call the guy. I figure your pretty close to 50/50 here, but the problem is you stand to lose 2BB if your no good, and only 1BB if you are good. taking this into consideration, as well as the fact that in shorthanded, all other things being equal, you should try to make the lowest variance decision, because the variance in short handed is a real bitch sometimes.
EDIT- WHOOPS! I didnt see you actually did have some numbers on him. 1.8? Eh, very marginal. I think id just call it. 1.8 is not all that mizorly for an SH player, over 2.2 or so and id probly reraise him.
Incidentally, speaking of Xas, my prediction is he will probably say to grow a pair and reraise this mizor