I have a set of Unigy II batteries, AGM's. I installed a few sets of IBE flooded lead acid for a couple neighbors.
I went with the AGM's because of the price, got them used for a steal, they were only 6 months old. A local forum member, Chuck Morrison, gave me the lead on them several years ago.
If I were buying new, would get a quality FLA battery. Witnessing how each battery will take a charge toward the top, the FLA are more efficient. You can "stick it" to the FLA batteries more so on the top. The AGM's are much less efficient towards the top.
My batteries as well as the IBE's I've installed, have almost the same charge current to AH capacity ratio, 20-25 to 1.
The obvious disadvantage to the FLA is they take more work, watering.