All the rentals have the same motor
My wife and I spend an afternoon on the lakes last spring. My though had been to rent a pair of water sprites, but her stated concern was that that would be more expensive than taking out one of the small Boston Whalers instead. So we went with the whaler. We managed to go pretty much everywhere we wanted on both lakes in an hour (we rented from the Wilderness Lodge), but the boat felt slow. It was disconcerting to watch the little sprites do laps around the islands in the middle of the lagoon and pass me several times.
It turns out that the whalers and the sprites both use the same engine, and the whaler being a much larger boat, this can dramatically affect the speed.
[[ Of course, it also turns out that my wife didn't want to drive a boat, and wanted to spend the whole time sunbathing at the nose rather than sit in a seat, so that part turned out just fine -- I got to take some of the best scenery around the lakes with me ]]