AGM's are among the class of batteries properly called Sealed Valve Regulated Lead Acid Batteries.. These are also called "Maintenance Free" meaning once they are initially "Charged" with acid/water mix you can not add later. If the batteries are hard to access. a good choice,, AGM additionall can be mounted on end, or sideways or other "Unusual" positions (no This side up) sticker
Otherwise they cost a bunch, and being "Sealed" and maintence free you can not replenish moisture that eventually boils off, this means they may not last as long as a properly maintained flooded wet cell. (Source, many web pages about battereies including the manufacturer's spec sheets for the batteries)
GOLF car batteries, specifically the GC-2 are very common in RVs.. You put two sis volt GC-2 Golf car batteries (Which are Usually flooded wet cells) in series you get 220-230 amp hours.. You can add DISTILLED water as needed (JUST below the bottom of the filler tube, not touching it) and they have an average life of 7-10 years properly maintained.
They also cost far far far far far less than AGM's and give you the most bang for your buck.
There is also a GC-12,, (12 volt golf car battery) but I do not know the specs on it.
I went with DEKA G-20s (A GC-2 class. 230 amp hours) when I replace my interstates... I would hate to try and wrangle 230 amp hours of 12 volt battery (A 4D would match that) as I could not even lift the G-20s. and I'm a big strong guy.. The assistant at the store lifted 'em and I slid 'em in place.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times