What city are you in that literally "every" UberX car (I'm assuming UberX because there are some strict requirements for the Black Car and up service) is messy and unwashed? I've had both, nice clean cars and awful cars. And you give the awful cars and drivers 1-star ratings. And if the ratings go too low Uber fires that driver (that's what one driver told me anyways).
But that's my experience, in Atlanta. I love Uber in ATL. And all the drivers I've talked to (maybe 8-10) like working for Uber. And a ride from Hartsfield to Buckhead? $50-60 with taxi, $25 with UberX.
I'm no Uber shill, but I guess I'm a fanboy.