I've stayed at both and the Parc Soleil is a touch newer and nicer. They both have a nice pool area. Decent bar and restaurant at SeaWorld right in the pool area, which can be good/bad depending on what you want.

The Seaworld complex is a big more spread out. Which I actually liked. It felt like there were less people even when busy. However, that can mean more walking around the resort...if you have small kids you may not like that.

Both were very accommodating for families. I'd return to either.