We have been using Priceline to book our hotels in Anaheim for at least the past 5 years. And have never had any problems.
So I thought I'd share with you some tips so you can make the best out of your stay.
When you go on Priceline, click on the "Name your own Price" button. Select Anaheim.
Make sure you are selecting "Disneyland Area" and the highest number of stars which I believe is 3 1/2 stars.
The starting price you should use is ALWAYS $50 per night. This will make it about $62 per night with taxes.
If they do not accept the first price, you will have to change the price and the star level. So for your next search, I usually go up to $65 and select 3 stars. But don't worry, even though you selected 3 stars, if there is a 3 1/2 star hotel available for your new price of $65 you will get the higher hotel.
Generally, if it's not a HUGE convention weekend you will get a very nice hotel for a very reasonable price. If it's the holiday's or a convention weekend I wouldn't use Priceline.
Positives of Priceline:
Low Prices, generally more than 1/2 what you would pay normally. Paying $50 per night for something like the Doubletree when you would pay $100 for HoJo's feels GREAT!!!
Negatives of Priceline:
No cancellations. If you book a room, and can't go or something happens, your stuck. (This has happened with us more than once), but it's the price you pay for saving $$ sometimes.
Inability to pick your hotel. If you don't have a car, or aren't planning on renting one, I wouldn't use Priceline. If closeness to the parks is your #1 priority, then I wouldn't use Priceline as the only hotel we have gotten that is within walking distance is the Anaheim Hilton, which we don't care for.
These are the 5 we have been getting over the last 2 years or so with the most frequency.
Hyatt Regency (Corner of Harbor and Chapman)
Positives: Easy to drive to Parking Structure, Clean, Comfy Beds, Starbucks in hotel, Target caddy-corner to hotel. Nearby restaurants include Buca Di Beppo, Red Robin, Joe's Crab Shack and Outback. Hook-Ups in rooms for DVD players/Playstation, etc.
Negatives: $12 per day for parking, shares bus with other hotels
Crowne Plaza (Corner of Harbor and Chapman)
Positives: Easy drive to parking structure, Clean, Comfy beds, Target across the street. Restaurants in same area include Red Robin, Joe's Crab Shack and Outback.
Negatives: $9 "resort fee" includes parking and internet. Weird parking lot and entrance behind the hotel. Room Service/Hotel restaurant closed at 11pm. Shares bus with other hotels
Doubletree Orange (near the Block of Orange on Chapman and The City Dr.)
Positives: Easy drive to parking structure, Clean, Comfy Beds. The Block within walking distance of hotel.
Negatives: $10 per day for parking. Room Service/Hotel restaurant closed at 11pm (even on New Years Eve!!!
Hilton Anaheim (Near the Convention Center)
Positives: Close to park, walk to park in 20 or so minutes. Renovation now complete.
Negatives: $15 per day for parking. Weird parking structure.
EDIT: With the renovations almost complete, the hotel is VERY nice, comfy rooms, big TV's, etc.
Hilton Suites Anaheim/Orange (Near the Big A)
Positives: Easy drive to park. All Suite hotel with 2-room suites. Free Parking. Gorgeous hotel. Clean. Comfy beds and pull-out couch bed. Flat Screen TV's.
Negatives: None as long as you have a car. Not sure if they offer resort transportation. Nothing listed. Hotel now charges $12 for parking.
Priceline isn't for everybody. I wouldn't suggest using it in an area you aren't familiar with unless you do some research. There are LOTS of sites out there that give priceline tips to other area's.
If anybody else has anything to add, please feel free to do so.