RoomAtlas.com lets you spot-check prices on a Google map and has TripAdvisor reviews waiting for your perusal in the sidebar.
What's hot: It's nice to look at a map and see a graphic depiction of hotel pricing. The simplicity of Room Atlas makes researching hotel rates quick and easy. As you browse hotel prices on the map, click on the price tag to get a summary bubble. On it you'll find the star rating, links to hotel details and reviews, and a link called Shortlist, the feature I like best. Click on that for hotels you're considering. You'll find your list on the lower left side of your screen with various price tags for comparison-shopping. I found hotels in the United States, Europe, Australia and Asia.
What's not: It would be much quicker if you could scroll over the price tag and have the hotel's info summary pop up. But no, it makes you click to see it -- and click again to make it go away. It would be more efficient if the summary disappeared once you scrolled off the price and you could go on to check the next hotel's info. Also, I noticed that the hotels' URLs were missing and some of the descriptions were outdated.