They each have their pros and cons!
OKW: Has the larger rooms, the overall theme of the resort is more definitive (SSR's theme is very understated to the point most people don't even know it has one lol), the balconies are larger (the balconies in one and two bedroom units are huge and have ceiling fans, a round table that seats four and enough space you actually feel like hanging out there), and the whole place feels like an island retreat. Olvia's is wonderful. The main pool is very nice, the quiet pools are also very nice. It has one of my all time favorite pool bars, if you go, get a Turtle Crawl!
NOw that the resort is getting a refurb, I am so excited to stay there again in the future because the new rooms look gorgeous. Although I love the old style rooms too!
On the con side for OKW (in my opinion only of course) its has nothing in the way of counter service beyond a lunch or two, the bus route is funky and seems to take a lot longer than SSR's route, some of the units are right on major roadways and are noisy and its not as walkable to DTD and in fact the path to DTD closes at dark. Even in the day, I probably would not let my teens walk alone to DTD, at SSR I would without hesitation.
SSR is a beautiful resort, very well maintained, lovely grounds with ponds, fountains and very nice walking paths. Its very walkable to DTD, it has the Turf Club which is outstanding and has Artist Palette which unlike Goods to Go at Olivia's has a much bigger selection of food and indoor and outdoor seating vs, the two or three outdoor picnic tables Goods has. The units are smaller but very nicely appointed and still spacious. I think SSR has the better main pool by far (as do my kids) and I like the second feature pool over in the Grandstand area.
To me you cannot make a bad choice. They are in the exact same location so distance to the parks will be the same. They are both large resorts with lovely grounds and both of them have rooms that may involve some walking. They both have a very laid back feel which is our preference over being right next to a park. We like to be able to get away from the hoopla!