I went to Typhoon this past weekend for the first time since Aquatica opened, so I couldn't help but mentally compare the two. They are similar enough that I don't think you'd want to do both in the same week--both try for a beachy, tropical feel. Given the layout, Aquatica "feels" bigger, and I think it has more rides. I also find Aquatica more relaxing.
That said, I agree with Gary, each park has its strong points--rapids ride at Aquatica is amazing and the non-slide views of the Commersons dolphins are fun, TL has the better wave pool (and, I would add, the unique Crush n Gusher).
I think the biggest thing to see is if Aquatica holds to its stated goal of keeping crowds low. My biggest complaint about TL is that we showed up only an hour after opening, and already every louge chair was taken. And during the Summer, the wave pool gets so packed you can barely move. This might end up giving Aquatica the edge.
Also, I don't have kids, but there seems a lot more to do at Aquatica than TL for kids, say, 8 and under.