Not sure where the bad reviews are coming from. I travel a lot, and rent a lot, and Advantage was a great price and fine service for what I paid. If the complaint is that they try to sell you insurance, gas, and other services, guess what, this is standard practice in the industry. Read the fine print of your contracts ahead of time and be prepared to say no to up-sells.
I had absolutely no problems with Advantage--rented the third week in February 2013. Fine car, excellent price, smooth process on pickup and drop off. Maybe ten minutes on both ends--totally acceptable for the rate I paid. The deposit hold on my CC dropped off a day before they said it would, too.
Will rent from them next time I'm in Vegas.