I've been to both, and would recommend the Renaissance. We stayed at Marriott World Center and really did not enjoy it. The pool water was really cold, the food court was terrible, plus we went when a convention of wanna be child actors/actresses were there.....not what I wanted to experience on vacation.. Renaissance was nice, and I bet even better since their renovation, plus you can't beat the location. We are looking at staying there again this year since we are doing Sea World, Aquatica, DC, and Universal, but will switch to the Hard Rock for the Universal part. But for the Sea World element, the Renaissance is great.