Luxury Link (luxurylink.com)
In addition to Buy Now offers (fixed-price packages for multiple-night hotel stays, most with many added amenities), Luxury Link has three types of auctions: Single, in which only one package is auctioned and you can increase your bid as many times as you like; Dutch, in which there is more than one identical package being auctioned and you can bid as many times as you like; and Best Shot, in which there is more than one package being auctioned but you can bid only once. There's no charge to register with Luxury Link or to bid, but each transaction carries a fee of $20.

To evaluate the site, we examined several recent Buy Now offers as well as all three types of auctions and then compared the results with what was available through other booking channels for the same type of room in the same season. Without a doubt, the auctions yielded better deals than the Buy Now offers, sometimes shaving as much as 50 percent off the best available nightly rate. The Buy Now offers can sometimes be a good deal if you count the value of the extra amenities. Still, when it comes to buying packages, we found that in most cases we were better off booking the room on our own and buying the extras à la carte. Two particularly good auction values were a six-night stay at Phuket's Banyan Tree Resort for $1,994, nearly half the $3,960 rate we were quoted when we called the resort, and the winning bid of $820 for three nights at San Francisco's Hotel Drisco, a savings of about $400 over other channels we checked.

Ross, who has successfully bid on at least a dozen Luxury Link trips in the past four years, recommends that potential bidders first contact the property in question, both to inquire about a better rate and to ensure that their preferred dates are available.

Andrew Harper (andrewharper.com)
A basic one-year membership costs $199 and includes critical reviews of top properties in the monthly "Hideaway Report" newsletter and access to the Q Club, which provides upgrades and exclusive rates with more than 350 supplier partners. Only members may participate in the site's hotel auctions, of which there are currently about 1,000 per year; the company hopes to raise that number to 1,300 by 2008.

A random sampling of recent Andrew Harper auctions provided the most impressive overall savings of any site we reviewed. Examples of luxury bargains we found included three nights at Rome's Hotel Lord Byron for $1,001, less than half the rate of $2,134 available via the hotel itself, and a three-night stay at Budapest's Le Méridien for $378, compared with $811 through the hotel's reservations line. Even one of the direct-buy (non-auction) packages was more than 50 percent off the lowest rate we could find anywhere else.

Andrew Harper doesn't bundle as many extras into its offerings as Luxury Link does, which makes it especially appealing to travelers who aren't interested in activities. The annual fee, which we initially thought a bit steep, can easily be earned back with just one booking. We were also pleased to confirm that the Q Club card does indeed confer significant savings of 10 to 25 percent as promised.