Another thing to consider is what life is like in the given community (deployments, crew dynamic, how much flying time etc...) I know there are airframes I was interested in that I lost interest in after finding out what it is really like to fly on them, what the culture is like etc... and there are airframes that I could have cared less about but upon learning more about how life is like on them I became interested.
As for the letters, I like how my flight is doing it, we each have to turn in a memo saying what our first choice is (whatever that may be) and why we want it/why we would be good on it. There really hasn't been any pressure to go to any specific airframe (Flt/CC is a JStars guy and the CV is a F-15E WSO)
