I live 10 minutes away and I used to go all the time. It's pretty good if you do it right. Here's my advice
1. Never go to the water park. It's filled with piss and blows
2. Go in the morning and hit Superman/BIzarro a few times then Batman.
Batman and Bizarro are the two best rides. Get there before the lines get really long. Later in the day check out the rest of the park