Sidestep is a fairly decent tool for getting a quick view of hotel availability for an area. Usually, I just want to see a list of all of the HHonors or Marriott hotels that have rooms available for my dates BEFORE I go run a bunch of searches all over the web. Sidestep gives me this with one click.

Most of the time, I end up finding a better rate elsewhere. But if I don't, I click-through Sidestep to the hotel site and book the stay.

This seems to work the best when you are looking for a 2- or 3-star place with a fairly basic rate structure (i.e., a Hampton Inn). Sidestep is less effective at searching high-end hotels, and totally useless if you are looking for something that isn't part of a big chain.

For flights and rental cars, I find it to be totally useless. The searches take too long, and always produce less complete results than the other sites.