You must have an ammeter to know when AGMs are truly full (when their amps acceptance tapers to 0.5a/100AH of bank at 14.x) And if you don't bring them to true full often, they sulphate. I use my Trimetric for that ammeter job.
You can tell when Wets are truly full with an hydrometer. You can overcharge Wets and just replace some water.
I have gone AGM but without my Trimetric I couldn't look after them. I also like that I can keep them inside the rig where it stays warm in the winter so they don't lose capacity in the cold just when I want lots of capacity with the furnace on so much. If the AGMS are outside in the cold, no advantage there.