Lovely park...been a few times. Pools are great....especially kiddie one, they'll love sitting on the elephants. One small problem is that the park is kind of midway between Cambril & Salou. Cambril is the nicer of the two towns, but I'd recommend going into Reus for a meal & just to enjoy a typical Spanish town (you know it's a real one when they don't have photos outside the restaurants & they have to hunt for the one english menu).
Cambril park is spotless, the huts are lovely, the supermarket is good value, restaurant & entertainment are pretty good. For the age of your kids, it's a great spot, you'll probably book again for next year.
Port Adventura (theme park)nis great, even with a wee one, as they have some fantasitic shows (it's part of the Universal Studios group)