Good bluff catch!

I rarely am able to call with Ace high. However, the UTG is just killing me with stealing pots away on the river in prior action (35 hands total though). UTG is 55/14/2.3. I decide to take a stand and I find that I'm good.

Full Tilt Poker $0.25/$0.50 Pot Limit Hold'em - 9 players - http://www.thehandconverter.com/hands/323938
The Official DeucesCracked.com Hand History Converter

BTN: $50.00
Hero (SB): $37.45
BB: $49.50
UTG: $67.60
UTG+1: $44.75
UTG+2: $11.15
MP1: $11.15
MP2: $19.25
CO: $52.15

Pre Flop: ($0.75) Hero is SB with As Kc
UTG raises to $1.75, 6 folds, Hero raises to $5.75, 1 fold, UTG calls $4
I'm trying to get more aggressive by 3 betting. I have a top 5 hand, so I will 3 bet this in and out of position on most occasions.

Flop: ($12.00) 4s Th 3s (2 players)
Hero bets $5.75, UTG calls $5.75
Standard cbet - 2 spades and it is certainly plausible that the villain is on a spade draw, given his playing 55% of hands.

Turn: ($23.50) 9h (2 players)
Hero bets $10, UTG calls $10
Doesn't change anything; I would prefer to take this pot down right here & now.

River: ($43.50) Qd (2 players)
Hero checks, UTG bets $15.95, Hero calls $15.95 all in
I have showdown value, but definitely don't like the Q. However, I call figuring I need to be right about once every three times (4:1 odds on call). In addition, given the way he played this hand, I believe he's playing a missed flush draw. Finally, the reality is that I was committed on the turn. $16 more is not going to get a fold out of me.

Final Pot: $75.40
Hero shows As Kc (Ace King high)
UTG shows Jh Ah (Ace Queen high) - not even a flush draw, just Ace / Jack high! LOL.
Hero wins $72.40
(Rake: $3.00)