You don't have to tip Uber but I usually do anyway.

It still seems like an amazingly good deal the few times I've used it. I live a little off the beaten path. The other day I needed a ride from my house to somewhere 35 minutes away. Everyone else I know was working and I didn't want to wait. The guy came all the way out to my house (20 minutes from where he was on the interstate) then took me to my destination for $36. Before Uber, a taxi would have either never come out here or it would have been at least $100.

Even with the tip it was cheap. And I just got a nice raise and don't mind sharing the wealth.