At the risk of being unoriginal or going the more popular route, I have to say very difficult due to sharing at least one of each member of the squad. Like I'll never be like Wrecker: I like to eat, but far from being a hulking muscular guy who can take out God knows how many thugs and monsters. But I suppose if we're going strictly psychological, it may be easier.
Of these six, I have to go Crosshair. That is not to say that I can't be selfless, protective, honorable, tech-savvy, or indeed mischevious every now and then. I sure as heck am not optimistic and/or emotional (or rather to an extent, anyway)...sorry, Omega. But which one am I most like? Sad to say, I think I fit the bill of being mostly introverted and pessimistic.