Unless you are facing a very tight player raise UTG, IMO AK should be always raised or re raised...

The reason is simple, it dominates a lot of hand some weak players call raise with. (Ax, KQ, KJ, K10, etc...) (As Beav said)

If you both hit top pair!! Vivaaaaaaa, LAS VEGAS...

Of course you will loose it more often than you win 6 handed, but if you win it 25% of the time, it's a winning play. And belive me, you have to max out the profit on every hand if you want to beat the game in limit.

Plus, of course you wont make limpers fold, but you will kick SB and BB out with bad hands avoiding situations like a flop K-2-9 with BB holding 9-2o.

Plus, a reraiser could kick some limpers out too, increasing your odds to win the pot. (however, you dont necesserly want it to happen )

Just my 2 cents...

KJ

Edit: Just rered beavis post, and I realized I said exactly, but I mean exactly, what Beavis did... Sorry Beav I just red your post too fast the 1st time... Thinking it was bullshit as usual!!!
Kidding of course