We purchased a pool from Water World this August. We love the pool, no problems at all. I'm not sure what problems other people have had with Water World, but they went out of their way for us. Everything was top notch. We priced Viking and San Juan pools. Water World is not cheaper as another poster had indicated.
We got the 18x44 8ft deep with jets in the seats, a heater and safety cover. Like I said we love our pool, and the customer service has been one of the best experiences we've had. They will be coming out to our house this weekend to show us how to close our pool. If you have any questions let me know.