Just used EZ's service after reading about it on Yelp and it was great.
I was in town for the Labour day long weekend and had never experienced Scottsdale's nightlife. I arranged a pick-up and drop-off with EZ got the price quote up front and asked a few questions about the local scene (after reading all sorts of horror stories on Yelp, I wanted to make sure my wife and I picked a spot we would easily enjoy). He was patient and answered all my questions.
The car arrived right at the estimated time, EZ got us in the backdoor at the Revolver Lounge so we didn't have to wait (there wasn't a huge lineup, but it was still nice of him to do that) and he was punctual with picking us up at the end of the night too.
I'd recommend this service over using a taxi for a couple of reasons. EZ knows his way around the nightlife in Scottsdale, you don't have to worry about a meter running, and he's got some pretty sweet tunes in his car.
Price is dependent on where you are coming from and where you are going, but it was still less than what I expected to pay for a cab, so I was happy.