We have used uber on Maui and it was fine. Just like uber anywhere else. I agree, drive yourself, much cheaper than tours and especially Uber/Taxis. You also have the considerable expensive of getting to/from your hotel/condo and the airport if you don't rent a car.
Do people Uber in Maui?
Ride-sharing services Uber and Lyft also operate in Maui. Many hotels and resorts – especially those in popular tourist areas like Wailea and West Maui — offer complimentary shuttle services to and from the airport as well as to nearby attractions and shopping areas.