We've stayed at both and prefer OKW. The room is significantly larger and the full size laundry room is really great, plus in some of the units, it gives a second entrance to the bathroom.
The dining area has a large round table plus a buffet/hutch area which is a TON of storage and shelves on the wall above it. We utilize that area for all our bags, souvenirs, etc. that we need every day.
The kitchen has a great island and full size bottom cabinets and counter vs. SSR with a narrow countertop and much less counter space. We cook almost every day and we like having a real workable kitchen. 2 or 3 people can be in there at once and not get in the way.
The jacuzzi can fit two people. That's fun too
If you have small children and want better pools, then SSR has 3 great theme pools. OKW has one theme pool plus quiet pools so better for older kids. SSR also has a food court whereas OKW only has a snack area next to the pool so if you want to eat QS at the resort, then you should choose SSR.
OKW has a small resort town feel whereas SSR has a large condo complex feel. SSR has elevators in every building but OKW only has them in a few.
If we could only get SSR, we wouldn't cry but we would always choose OKW over SSR for our needs.