I vote you go Marines But
I was a Fire Fighter in the Marine Corps. It is True that your primary job is crash or Airport Fire Fighting. If there is as fire on base in a Hanger or Chow hall you can bet your rear every Fire fighter on the base will be there, military or Civilian. It is not True that you will not deploy, if you bid for a Wing Job you will see the world in its entirety. Wherever you see a Marine Corps Air Craft you will find a marine with a MOS of 7051. At the DOD Fire School Lewis Garland Fire academy you will get the same Training that all branches of the Service get at the Basic Level Except the “Navy” This includes FF1, FF2 Airport Fire Fighter, Has Mat Tech and Some sort Medical training. It is a joint school thought by members of all branches of the Military. The Navy gets some basic firefighting in school and then once they get to a Ship the whole ship does Annul or semi annul training at places all over the Country. There is one at NETC in Newport R.I. The Training they receive is Shipboard based and revolves around survival on the open seas and Fire Systems that are unique only to ships. The Air force By Far has better equipment and continuing training. There Trucks are Newer there Stations are impeccable.
The Veterans Credit Points you speak of are a whole other story. You need to talk to you local civil service office to see how you can qualify. There are only certin dates and theaters of operation of people who served that are eligible.
I know this is a lot to take in feel free to email me and I will try to do better to explain. By the way I also worked in the Federal system @ Army and Navy installations. Good Luck