As you can see, everyone has their opinion and most can back it up with some sort of a study or article. We've used Lifeline AGM's for 6 years on 2 coaches and have found that the AGM performed as well as we could have wished. The big selling point for me is no need to add water, and absolutely no corrosion....EVER. At each maintenance cycle I use an air hose to blow the dust off the batteries and that's it. No clean up, no hold down corrosion and no terminal corrosion or cleaning. Also no need to remove to clean the battery tray, counteract the rust and repaint. To me, this makes AGM's worth it.
By the way, we boondock extensively, have 560W of solar panels on top, and use the RV a lot. 32,000 miles in 16 months.