If eating or other activities at DS will be important, then SSR because you can walk there or take the boat or bus. From OKW it's really boat or bus (there's a walking path but it's open during daylight hours only), and it's farther from the SSR action.
Also, all of the SSR buildings have elevators, whereas only a few OKW buildings do. Bell Services will help carry your luggage up to your room, but if anyone in your party would have trouble with stairs, I'd recommend SSR.
OTOH, OKW has the largest villas on property! Are you planning on a studio? If so, the OKW studios all have two queen beds. The SSR studios have one queen bed and one queen Murphy bed that folds down to cover the couch. It's a regular mattress, so still as comfortable as a bed, but being able to put the Murphy up during the day gives you more floor space.
If swimming pools are important to you, SSR has two feature pools with slides and two quiet pools; OKW has one pool with a slide and three without.
Both resorts have multiple bus stops and bus-only transportation to the parks, so no real difference there.
Both resorts are spread out across beautiful grounds, including a golf course (the golf course at OKW winds around and through most of the resort whereas at SSR it's only in the Grandstand neighborhood).