KK - free showdown with A on board?

I think a raise on the flop here is the best play. What are the likely hands your opponent is on?

A-rag: In this case, he will call your flop raise, check/call your turn bet, and check allowing you to check for a free showdown. You lose out on 2 Big Bets.

Two pair or a strong ace: In this case he will reraise you on the flop, which you can safely fold. You lose out on 1 Big Bet.

Check/Calling will lose 2.5 Big Bets if he has the A.

If you have the bettor beaten at the time (he is on a draw or has middle pair), you may win the pot right there or you may get some more bets out of him on the flop and turn. Does anyone disagree with this?