I have used Priceline a number of times for HOTEL reservations and have been satisfied 90% of the time. There are some caveats ou should be aware of the biggest being know what the competition (pricewise) is in the area you are travelling and 2) know what area you are bidding in for you may get something you do not want.
If you plan to use Priceline for hotel reservations you absolutey need to visit
http://www.biddingfortravel.com before you ever go to Priceline. This site will tell you the locations where (State/city) Priceline has hotel vendors...who the vendors are, and you can actually go to a BB and see who has been awarded rooms and at what price.
Check out this site and then if you have any further questions, ask away and i will see if I can answer them.