I've used Lyft several times, and had heard good things about Uber, so decided to take advantage of the "free first ride offer" that I had missed out on with Lyft. This turned out better than expected!
My driver, Shawna, was great! She arrived in less than 5 minutes and was friendly and attentative. We chatted briefly about sports and the usual. We also talked about how Uber was doing in the Phoenix valley, and how this ride was comparing to the usual taxi ride I used to take. The ride in her car was comfortable and it was obvious that she took a lot of pride in her service.
This same trip in a local taxi would have cost me $40 with tip. Because of the Uber promotion, the ride was free, meaning it would have been under $30.
I really cannot see myself ever taking a taxi again in areas serviced by Uber (or Lyft). Give them a try - you won't be disappointed!