For any given size battery there are basically two capacites
Most everyone, Lilfeline, MK, DEKA and more a G-27 is about 100 amp hours. Larger batteries have more amp hours. Smaller ones less.
OPTIMA, which is a special case. it's about 75 AMP hours for a G-27 (NOTE: these figures are approximate and intended to show the shortcoming (AMP HOURS) of Optima for RV use)
Optima does have it's place and in it it's the very best there is. Motor Homes and Trailers ... NOT that place (It is a different type of RV)
I usually tell people this
First: As AGM's go Lifeline is the best. I do not know if they are worth the difference in price though (You will have to decide for yourself)
If maintence and ventelation is NOT a major issue (Some coach makers put batteries in the most god awful places) then I'd go with flooded wet cells.
Best bang for your buck, no question about it.
But as I implied. sometimes maintenance and ventelation ARE issues.
Home is where I park it!