I did AFROTC. About 50% or so get a pilot slot out of ROTC, but if you're a senior and 2.2 gpa you probably wont be competitive out of ROTC. I've known guys with low gpa's get a slot in rotc, but they started the program as a freshman or sophomore and held leadership positions. There are about 500 slots each year out of AFROTC, almost 600 out of the Academy, and i think around a 100 in OTS. Active duty slots are around 50, with about 250 applicants this year (changes year to year). It's a 10 year commitment once you finish pilot training. Also, rumor has it that Marine Corps has guaranteed pilot slots if you meet the requirements, and my roommate did Navy ROTC with Marine option and I think he said they make them all do OTS anyway. Also, Air Force has the strictest medical requirements, and if I could do it over again I'd go through the Coast Guard because currently the AF medically DQ'ed me.