OKW rooms are bigger, and the resort is older. Some reports say that the rooms are showing their age (anyone else can feel free to dispute this, it's not my own firsthand knowledge). They're both fairly close to Downtown Disney, though Saratoga Springs is closer. Some sections of Saratoga Springs, you could walk over in less than 10 minutes if you don't dawdle. The counter-service eatery at Saratoga (Artist's Palette) is bigger than the one at Old Key West (Good's Food To Go), but it often takes a while to get your food even when it's not busy. I won't tell you to where to stay, but if you stay at Saratoga, request to stay in the Congress park section. You'll be a 5 minute walk away from the main building and main pool, but you'll also have a quiet pool close by, AND you'll be within walking distance to DTD, where you'll have many more dining options.