Interesting hand. If you assume that the BB will play AK,AA,QQ the same way preflop+flop, you are a 2-1 favorite to have the best hand on the turn, I wouldnt worry too much about the MP2 guy since it looks to me that he is on a flushdraw given the way he played the flop and turn. So I think checkraising this turn is right move. If you are 3 bet I would call down.