Summer Bay has several different sections, some nicer than others. The overall resort has a nice slate of amenities, but it's a bit farther from the parks.
Orbit One is a smaller resort, very few amenities. The units are reportedly clean and well-kept. I put my father up here a couple years ago, and he liked it a lot (and his wife is a little picky about cleanliness).
If it were me, I'd probably lean to Orbit One, mainly because of the location. The only exception: if you're talking about the *Houses* at summer bay, that would be a better choice. They have private pools, and are 3BR homes.