I've used them 4 or 5 times over the past 2 years, always calling in around 11:30 PM - 1 AM. They used to be fine but have gotten progressively worse.
First couple of times, maybe 15 min wait. The dispatcher was friendly, saying to call back if the cab didn't show in 15 minutes or so.
The next year, it was more like a 30 min wait.
The last time I called, there was no cab. All I got was a return call playing a recording about how I wasn't going to get a cab.
Update: I had to use them again as there are no other cab companies. They came, but only because they stalk E Carson St after 2 AM and not because they actually took down my request. I know this because I lost a phone in the cab and the dispatcher couldn't find the request ever being recorded when I called in 5 minutes later to try to get it back.
On a positive note, they were helpful in returning my phone once it was found. I really appreciated that the dispatcher went to check for it in the cashier station on a Sunday, when she could've told me to wait until Lost & Found officially opened the next day.