I'm running a Super Start AGM (Deka Intimidator) in my camper. It's only three years old, but so far seems to be a great battery. Very good capacity!! I wanted AGM so it could be inside without the need for venting, but if venting and mounting position aren't concerns, I would recommend a standard flooded deep cycle battery as more cost effective. (At half the price, with the same capacity...)
FYI, all the "Super Start" batteries at Oreilly's are actually Deka batteries, and the rebadged "Intimidator" gel batteries are quite a bit less expensive than if you buy the Deka branded ones. I just picked up two Super Start (Deka) Marine/Deep Cycle flooded batteries for the RV we're moving into full-time. My setup should never take them below 50%, and I have enough solar to easily get them full charged on all but the worst of days here in the desert SW, so I expect they'll last longer than I have the RV.
I think the most critical thing about battery life is how it's treated... I can kill ANY new battery in a week, and I'd bet that I can make just about any battery last 10 years, depending on how it is charged/discharged. I've got a Mexico Optima in my Jeep that's still going strong, and it's 5 or 6 years old, but the trouble with Optimas is that they are built as six little round coils, and hence have much less capacity that a similarly sized rectangular plate battery that uses all the available space.
