crazyforpooh,
I think Hotwire can be great! It is especially good if you do not care what SPECIFIC hotel you want to stay at, but only care about the quality and location. To me, I would be equally happy staying at any 4* hotel at a 2* price. The brand doesn't really matter. You can get really great deals this way.
A couple notes,
1. Compared to using priceline, the prices on hotwire are a little higher for the equivalent hotel, BUT you get a list of amenities (pool, business center, golf, etc.). Sometimes based on the list of amenities, you can figure out what the hotel is. Some think it is worth paying the extra $5/10 per night (compared to priceline) so you can be guaranteed the amenities.
2. I think you are only guaranteed space for 2 people. So this may be a problem. If you are going to a popular family tourist place (like Disney), most of the rooms there will have 2 double beds, but it might not be guaranteed. We used hotwire this past June at got the Walt Disney World Dolphin for $81. We got 2 double beds no problem.
3. You pay up front and there are no changes. So don't use hotwire if your plans may change.
Also, there are a couple websites that help you using hotwire and priceline. Check out:
http://biddingfortravel.com or
http://betterbidding.com
If you have other questions, just ask. Those were the things I immediately thought about.
Maggie