Not to buck the trend here, but we went the first time when youngest DS was 3 1/2 and he was in heaven (my other 2 were 5 and 6 then and loved it too). As I recall, they could do most of the interactive rides - Pirates, Aladdin, Jungle Cruise, and even Mighty Ducks with the special (non-moving/joystick) controller. But the unlimited video games were what thrilled them. I was worried that DS3 would lose his card being so young, but we made sure he had pockets and he treated that card like it was made of gold (which it basically was since it meant he could play EVERYTHING!). He'd swipe it, then c a r e f u l l y place it back in his pocket, then play.
There were also a lot of imagination areas where they had a blast making music CD's (which we still have), toys from Toy Story, and morphing their faces, etc. on the computer. I guess I'd say, especially with boys, if they are computer and video game literate, there's definitely enough if it's one of your plus options to fill 3-4 hours. If you're paying out of pocket, if they're girls, or if they don't really care for video type stuff, maybe I'd pass.
DQ was originally meant to be a "Disney Park Fix" for people living away from the actual parks. In no way does it compare to the real theme parks, so if you have your choice, I'd stay with the theme parks instead. That said, I know we'll be using at least half our options next summer to go to DQ with my 3 boys (who'll be teens or close to it though by then!). Basically, you'll be fine either way, but if you have the option, I'd take it for them over Pleasure Island or the waterparks if the weather isn't cooperating.
