We just stayed one night at the Sheraton World Safari, adjacent to Sea World. The website says walking distance to SW, but it really isn't unless you are really into long walks.
Request a room in the tower as they are newer and do not have door that open to the outside. The rooms have the "heavenly-type" beds that are at the Westin. I don't remember what Sheraton calls their comparable bed. But, it is comfy and the room was clean and nice. The pool is not just plain. It is surrounded by lush gardens and looked really nice. The food choices are slim and pricey.
I reserved the room on Sheraton's website because it was WAY cheaper than priceline. They had a "web-only" pre-pay special for $68 a night! The advertisied regular price was something like $175 to $200 per night. This price was a GREAT deal and well worth it.
It was as comfy as our room at the Polynesian but, without the wonderful Hawaiian decor!
I will say that I would not pay more than $100 per night to stay there--especially if they stuck me in one of the "cabana" rooms which are the old ones that have the outside door. They are far away from the lobby and restaurants and pool. The price you paid will determine your level of satisfaction! At $68 a night--we were VERY pleased.