Yes, I've also gotten universally positive feedback from all of the Uber drivers I've talked to (Uber Taxi, UberX, and Uber Black in SF). Whenever I take non-Uber cabs, I ask about Uber, and the response is also usually positive. Some of them say they have already applied to Uber and are waiting to hear back.

The one negative thing about Uber that I've heard is from a non-Uber cab driver who said that Uber is bad because it cannot be anonymous. He then told me about all of the people he has driven who are committing crimes and marital infidelity, which are not the best examples to use. To be fair, I can think of much better examples where anonymity is valuable.

I am a HUGE Uber fan and regular user, but he did make a good point about the loss of an anonymous travel option for those who need it.