[theFONZ]

First, what does he want to do? His choice of job may dictate one or the other, but they mostly have similar career fields.

Second, where does he want to go? Air Force bases are smaller and spread out everywhere. Navy seems to cluster around certain areas with a couple exceptions.

Standard of living will be close with either, but I'd put the nod to the Air Force as the best.

I'm in the AF, but I've spent tons of time with all services. I've spent time at various Army, Navy, and Marine installations and worked side by side with all of them extensively. With all that joint experience, I'd still choose the AF in a heartbeat. That's just me though; everyone's personality and experiences are different.