IMO, the value of AGMs for the average RVers is essentially zero maintenance, which for most owners translates into a relatively long trouble-free life with little or no effort. Let's face it - most owners aren't gung-ho on the tech maintenance stuff, especially between trips. There may also be an advantage in being a sealed battery (no venting required, oddball positions are ok), but that's important for only a few uses.
Compared to the commonplace Marine/RV battery, an AGM lasts longer and performs better, but compared to a golf car deep cycle it is merely expensive and slightly less capacity. The only significant advantage there is the lack of maintenance worries. Vs a 6v golf car battery, any improvement in charge cycles or depth is tiny (if any at all). All lead-acid batteries suffer from depth-of-discharge effects; the further and more often they are discharged deeply, the shorter their lifespan. Marine/RV hybrid batteries are especially harmed by that, but a quality flooded cell deep cycle and an AGM are pretty much the same.
This may sound as though I am anti-AGM, but that is not the case. I bought them for my own RVs.