Personally, I prefer French Quarter, but let me play both sides here.
French Quarter - Smaller, quieter, better decorated and themed (in my opinion). On the other hand, there isn't as much recreational activities, there is only one hot tub, and it's small, and because of it's capacity and the fact that they never really have an issue filling rooms, it's very rare (if ever), that they offer any kind of discount, deal, or incentive.
Riverside - I haven't stayed here, but I would jog through it when staying at FQ. It certainly has a lot more to do, seems to have more privacy, and more access to pools and hot tubs. Their theming is also a lot grander on the size scale than FQ. On the other side, it's HUGE! If you don't pay for a preferred room, you could possibly be staying at the other end, which means that it is probably a 5-10 minute walk. In my opinion, the signeage isn't that great, so navigating around isn't it's strong suit.