Have used Apple in the past but have used Walker Mobility the last couple of years. Walker has lower rates and scooters have never given us a problem, we did have a flat in Epcot 2 years ago but Walker had it repaired in less than 30 minutes INSIDE the park, they keep people on Disney property for super quick service. Just rented from them end of March and they were over $30 a week lower than Apple.
BTW-If you have the time take the Kennedy Space Center Tour, really great day away and they know allow access to the VAB (Vehicle Assembly Building) which is amazing in itself.