Another thing to consider, having recently separated from the AF myself... Going AF doesn't guarantee you'll end up getting a CTO. I was only in ATC for about 3 years after I retrained from maintenance, but I ended up leaving with only a radar ticket. So that pretty much eliminates me from doing any kind of contract work at a tower... and DoD jobs are like winning the lottery more so than the FAA from what I understand.
All things considered, I would probably be more comfortable waiting out your shot at the FAA, since you have 6-7 years. That is, unless you think you might actually stick out the 20 in the AF, but if you can, you're a better man than I
I'm now hanging on by a thread, just turned 29 and waiting for my VRA "front of the line" privilege to kick in... which I hope it does at some point here before I go insane.