Nellis will see the most traffic and obviously Vegas is well Vegas. Dealing with Red Flag multiple times a year will really get your adrenaline going.
Tyndall is great, they have that awesome beach access. Panama City is decent but don't expect a lot. Huge party town though during spring break. I don't think traffic count is that high. Last I knew it was a training/test base for F-35 and that was it.
Eglin is busy and steady. Pensacola area is much larger than Panama City.
Tyndall doesn't have F-35's. They have 3 squadrons of F-22's. One is a training squadron and two are operational units. The rapcon also works Northwest Florida Beaches intl and several smaller satellite uncontrolled fields. Although no where near as busy as it used to be when they had the F-15's and before KPFN closed, it's still a good mix of military, GA, and commercial aircraft with lots of practice approaches. Also, when all the MOa's and restricted airspace are active ( which is often) your airspace becomes extremely restricted and become rather complex. I spent 6 years there and although I liked the rapcon, Panama City itself sucks. Spring break is great if you're under 25 otherwise it's just a hassle. There is a paper mill which smells horrible and you can't escape it. You'll never get used to the smell. I dry heaved from it my first night there. The beaches are awesome. There are only about 5 bars and restaurants worth going to and you'll get bored of them after a few years. The DoD civilians that also work in the Rapcon are a great group of guys but you better not be sensitive lol. All Eglin will teach you is how to bust airspace without point outs and how to utterly fail at coordination with surrounding facilities. Ft Rucker and ZJX will agree with me on this. And Eglin is the place with F-35's but they come to Tyndall for practice approaches.
additionally, everyone I used to work with who was picked up on this last prior experience bid has been sent to level 10+ facilities. I'm sure it's the same for people from Nellis and VPS too though. If future FAA is your goal.
Nellis - High volume traffic....in Vegas. So yeah. Hot as hell though. My buddies that were there say McCarran was a pain to work with.
Eglin- F-35 training base. Used to be very slow. Don't know about traffic volume now though. Ft. Walton Beach/Destin is nice.
Tyndall - Pretty good traffic volume with the F-22s being there. I don' care for Panama City though. More like lower Alabama than Florida. Eglin is kind of the same but nicer looking.
Moody is a base in South Georgia a few hours from Tyndall and Eglin. Not too bad of an area, college/military town of about 50,000 people. Has a couple A-10 squadrons mixed in with some C-130s and HH-60s from the Rescue Group. Works more civilian traffic than anything. It has your MOAs and Refueling track along with restricted area gun range. Only 1 other controlled airport in the airspace which only has 3 commercial regional jets a day. Airspace has quite a bit of GA. Has about 6 or 7 uncontrolled airports with 2 of them being pretty busy at times. Its about 2.5 to 3+ hours from Atlanta, Tampa, Orlando, Savanna, and Daytona. A little over an hour from Tallahassee. 2 hours from Jacksonville. I would prefer Moody over Tyndall or Eglin just because of its location in reference to other nice places. But that's just me.
Here at Tyndall now. 2 squadrons of F22's, 1 squadron of T38's, and every 2 weeks or so, 10-35 visiting fighter aircraft that stay and practice live fire for 1-2 weeks. Panama City is basically in Alabama, but the beach is very nice. The base itself is pretty sucky. I would recommend Tyndall as long as you don't expect too much.