Have stayed at both the Mansion side and AB (and have stayed at POFQ, too)
I liked the theming of AB *much* better. BUT....if you are assigned a second floor room, there are no elevators, and even the first floor rooms are built up off of the ground, so if you have any mobility issues, or kids in strollers, or a lot of stuff, it can be difficult. However, the rooms at AB have a trundle bed, which is kind of neat if you have a fifth person to accommodate, or even two kids that each want their own bed.
The theming of the mansions, in my mind, is kind of "blah"....I know it's supposed to be plantations that get increasingly rustic as you travel down the river, but if I want to stay in a mansion-themed area, I would pick POFQ, which is a much more compact resort and is more romantic, in my mind (moss-draped trees, wrought iron, cobblestone "streets").
Both the mansions and AB have sections that are kind of a hike to either the main pool or the food court. I never measured it on Google Earth, but it seemed like the walk from our building at AB (building 36, facing parking lot) was longer than distances we've had to walk at other resorts, like POP. And of course, when we stayed in the mansions, we were assigned to building 95, the furthest mansion in the opposite direction!
The pool is nicely themed, and there are activities going on like a fishing hole, carriage rides, marshmallow roasts, etc. There's a marina where you can rent boats and boat transportation to DTD.
The lounge, the River Roost, is nice (my husband likes that they have Louisiana beers from Abita on tap!) and there is a great show there 4 nights a week (Yeehaw Bob...family friendly, but can get crowded!)
