Lifestyle, lifestyle, lifestyle. pick one that suits your lifestyle. Im lazy, love to travel, and love working with big crews. So Heavies was the way to go for me. If you fly fighters youll definitly have fun, but youll miss out on those lovely 2 week trips touring through Europe, no overnights in Honolulu, etc. If you want to see the world, go heavies. if you want to pull G's and study all the time and do all that stuff, then go fighters.
No one way is better than the other i think, its just about what you want. All i know is, when im 40, im going to feel a lot better about stepping into the cockpit of a C-17 as a reservist than an F-16, but hey some people age better than others.
As for the AF as a stepping stone for the airlines, this is where i might disagree with others. The airlines has ALWAYS been my passion. There is no problem in my opinion of serving honorably in the AF, doing your job well, and then moving on to the airlines. The military is an awesome deal and its extremely rewarding. Even if thats your intention from the beginning, then thats your perogative. Dont let anyone intimidate you. The first thing i said my first day at the Air Force Academy was "I want to be an Airline Pilot." Looking back at that, yes, it wasnt wise, but hey i was being honest. And I did my active duty time well, and now as a reservist im proud of what ive done, and i get to do what i wanted to do on both sides. Even at UPT i wouldnt hide it, youll know who the cool instructors are and who you can talk to about stuff like that. Good luck to you!