There seem to be a few other reviewers here that had similar experiences, so I'll just cover the key points: bait and switch tactics, hidden fees, no clear policies, misinformed staff, unavailable equipment, terribly maintained vehicles.
There are so many other places around Vegas to rent nice cars, so avoid these guys at all costs. For an exotic rental, there's Hertz prestige collection for example -- the pricing is the same and the cars are well maintained and new. For offroad vehicles/jeeps... just stay a way from these guys... their fleet of banged up, barely running high-mileage offroaders is a joke at any price.