I have used it many times for hotels and car rentals. The experience has been good. Before you plan to bid, do some research on which hotels are being accepted and the price. Go to biddingfortravel.com. They have hotel lists for the areas and prices which were accepted. They can also give you a bidding strategy. When you bid on Priceline, you cannot bid for a specific hotel, just a category (star rating) and an area. I bid for 2 nights in Orlando, resort category in WDW area and got the Gaylord Palms for $93 a night. Recently, some people who have been bidding the 2.5 star category have been getting the All Star Sports or Music for about $36 a night.
I have also won bids for cars and hotels in San Francisco and in Hawaii which were all good deals!