Generally, the Air Force. It's military of course, yet more like being a civilian than being in the Army or Marines. Long ago I was in the Marines, then the Air Force.
Better at what? Air superiority? The Air Force, but you won't be flying. Infantry? Obviously the Army is better than the AF at that. So what do you want to do? That's what it comes down to. You'll be more comfortable in the AF, I can say that much.
Air Force has prettier women and better housing. If you're enlisted you'll likely be bored to tears though.
Join the Marines or Army if you want to be hard. A lot of people take pride in having to go through more physically taxing obstacles (BCT, AIT, Airborne, Ranger, SF, MARSOC)
Either way it's up to you.
Personally, I find the Army to have the most options when it comes to fun jobs. Although the Marines have a brotherhood that just can't be matched.
Any service is awesome though and nobody will look down upon you for going with whatever one you choose.