I called to be picked up, about 10 minutes off the strip. I was told it would take 20 minutes. When I called 20 minutes later, I was told it would be 20 more minutes. The cab arrived 25 minutes later. When I called the dispatcher to tell them that I was not happy (at the 40 minute mark, shortly before my cab finally arrived), he told me he could cancel my cab, or I can wait.
The driver was competent and friendly. (As was the original driver who took me out to meet my friend, who gave me the card I used to call for the cab to pick me up.)
tl;dr: Took them 45 minutes to pick me up, 10 minutes off the strip, after they told me it would be 20 minutes. Rude dispatcher. Fine if it's the next cab in line at the hotel, but never call for a pickup.