I see lots of people bidding on Priceline here on this forum, but I'm perplexed because it only guarantees you a room for 2 people. Am I missing out on something here? Is it possible to figure out which hotel I'll get or are people just throwing caution to the wind when booking?
PPs already gave you some good information.
PL only guarantees double occupancy (two adults). That can be an issue in some cities where the room given to PL customers has one double bed without enough room on the floor for even an air mattress. Two queen (or double) beds is the norm for hotels in Orlando. Families rarely have an issue getting a room with 2 beds. There is a small risk. I recall one poster being given a handicap accessible room with one K bed. Hotel was fully booked. The hundreds of other posters in various internet boards never had an issue in Orlando. Hotwire asks if you have 1,2,3 or 4 guests. You'll get appropriate bedding. Hotwire tends to rate hotels higher then PL. When the same hotel is available on both PL and Hotwire you can (almost) always "win" the hotel on PL for less then the Hotwire rate.
ckergald gave some interesting advice. Generally you have to be prepared to accept a hotel which hasn't yet shown up in any of the "help" sites. Generally you have to accept the possibility of an, unwanted, upgrade. Buena Vista East doesn't offer any hotels higher then 4*. I don't think there are any other hotels in that zone which qualify as 4*. Double check. PL could change the map, very slightly, and move the Gaylord Palms into the BV East zone.
ckergald is right about using free rebids to "troll" for the lowest available rate but wrong about how many rebids are available.
http://www.biddingtraveler.com/ is a site which automates your bidding process. Using more "advanced" techniques you have 31 one bidding opportunities 30 "free rebids" I think the minimum bid suggested on biddingtravler is too high.
It takes way more then 10 minutes reading the FAQ on BFT before a reader knows enough to intelligently post and not run the risk of being "slammed" by Sheryl for wasting her time. The links to PL and Hotwire on biddingfortravel are affiliate links. BFT gets a commission. Use them if you're getting helpful information from the site.
There is a poster on Flyertalk (coolwulf) who has a thread discussing his site. You provide your dates, zone and * level. He gives you a "suggested" minimum bid which is on the money. Bid immediately and you won't be overpaying. There is a small charge for his service.