Gatorland has more to offer the whole family and you can pretty much be assured that there will be SOMETHING there you like. The gator wrestling is way cool, as are the young guys who do it.
Airboat rides (and Boggy Creek is just one operator) are a much more laid back nature experience, which is great if you're inot that sort of thing. And there is a possibility that you might not see all that much. Gatorland, on the other hand, is crawling with gators, including some awesome 15-footers, maybe even bigger (I've forgotten).