San Diego is rather nice, no insects, but you have hills to climb.
From what I saw (my MOSes were 7242 active and MP in reserves)...
the grunts get to shoot and play war more than everyone else, but Marine infantry humps a lot. Back, knee, and foot problems. Plus, they are in the field a LOT.
MPs...get to ride, shoot a lot, plus switch off from field MPing and LE work. Bad part is that even in garrison they works LOTS. Police work is 24 hours.
Cooking and warehouse sucks. Fuel is messy, boring, and a 24 hour job in the field.
Water is nice, lots of work during certain hours in the field, but not at others, and everyone is nice to you.
Intel...not James Bond, and not a lot of shooting, but you are more in the know.
Wing...lots of hours and no shooting in most jobs, but lots of good times and okay living (no where near as nice as the Air Force) plus the fmaily housing tends to be good.
Sensors is good duty.
Arty does a lot of lifting and digging to serve the tubes, not a lot else.
I was in the DASC, we ran the air side other than fighter attack. We gt to know what was going on, and only worked in the field (worked a LOT there) but shooting totally depended on the unit Sgt Maj. We had one that was way cool, lots of shooting with him.
The big problems are that the real manly and cool jobs are by tryout, recon, MSF, MSG. Even if you have an MSF contract you still have to pass the admissions.
The fleet anti-terror teams look cool.
Get everthing in writing on the actual government enlistment contract form that you sign. I know the recruiter seems like one hell of a man and Marine, but those that don't flat out lie mislead by careful word choice.