I'm from Spain and I just moved to SF. My first experience with Uber was 4 weeks ago (in Spain the service is banned) and it was amazing, very easy to use. Also, in another Uber, I had some cancellations problems from the drivers and Uber customer service is excellent.
Just 3 days ago I took my first Lyft, and well, it's the same I think. But for me, the Uber app has a better UX and it's more clear how to use it.