Considering the first reviewer, I wouldn't recommend taking their services from a hotel.
However, they do offer shuttle service from the airport. You prepay, so there is no way the driver can hammer you for more money. Just look for signs at baggage claim that say "Airport Shuttles" or something like that.
There are actually two separate companies. This one was a bit more expensive, but the other one only took cash. And I forgot to get cash before leaving for Vegas. So I had to go with this one so I can charge it.
Use the airport shuttles, it's cheaper. I think it was $6 or so per person to the hotel. Much cheaper than a cab. They have the prices posted outside so you can check it out when you arrive.