We used Expedia to book our Cayman Islands trip earlier this year and had no problems whatsoever.
Consumer Reports Online had an article about booking hotels online. I copied the text and will paste it below. Hope it helps!
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Hotel-booking sites: A comparison
Travel is the single largest slice of Internet commerce, and while airline-ticket bookings dominate, the percentage of hotels booked online is rapidly growing. There are bargains to be had on the Web, but there are also risks. After conducting extensive testing of Internet hotel-booking sites, Consumer WebWatch uncovered some surprising results, and offers practical advice.
Consumer WebWatch conducted repetitive, real-time, apples-to-apples testing of five of the leading independent sites: Expedia, Hotels.com, Lodging.com, Orbitz, and Travelocity. The results provided by these sites were compared with results found on a leading global distribution system used by travel agents, as well as branded hotel chain sites. The testing simulated a variety of trips in 30 cities throughout the U.S. and the Caribbean. Consumer WebWatch's research detailed the best and worst sites for searching for hotel rooms by price, location, star ratings, and specific brands and properties.
AMONG THE MORE SIGNIFICANT FINDINGS:
Questions of bias in integrated travel Web sites still remain; specifically, why products are listed in a particular order. One of the more disturbing findings was that none of these five sites--Expedia, Hotels.com, Lodging.com, Orbitz, and Travelocity--provided easy functionality to obtain the lowest hotel rates during the first search. Obtaining lowest-to-highest listings by price required more advanced searches, when available. Further, these lowest-to-highest search tools were not always clearly labeled for consumers to find easily.
Overall, Travelocity provided the highest number of lowest rates: 29% in 150 tests, outpacing its nearest competitors, Orbitz (21%) and Expedia (17%).
The advent of "Web rates" was a potent factor. In 85% of the tests, one or more of the sites provided lower rates than Sabre, the largest global distribution system used by travel agents. (However, the poor performance posted by Sabre does not mean that travel agents have lost a competitive edge, although they may have to work harder and use a variety of tools to find the lowest rates in exchange for your service fee.)
In many cases, some of these sites failed to provide rates for certain chains or properties when rival sites did provide them. This may reflect on either or both of two factors: 1) the inventories of hotel rooms maintained by these integrated travel sites and 2) the commercial agreements between these sites and the hotels in question.
Overall, the branded sites maintained by hotel chains and specific hotel properties performed rather poorly. But there was one significant exception: When rates were queried at specific properties, the branded sites outperformed all competitors except Travelocity and provided the lowest rates in 1 out of 3 cases.
On-site advertising may confuse some consumers. All five of the sites Consumer WebWatch examined--Expedia, Hotels.com, Lodging.com, Orbitz, and Travelocity--accept advertising from travel suppliers, including hotel chains. This may even include advertising embedded in the listings of rates, which some consumers may not even recognize as ads.
Despite specific queries for hotels in certain locations, some sites provided rates for properties that were nowhere near the desired areas.
The more a consumer shops for travel online, the more he or she is likely to conclude that it's a confusing world on the other side of that screen. To help, Consumer WebWatch has compiled a detailed list of tips to help make booking hotel rooms online much easier. Among them:
Keep shopping around. It's advice that Consumer Reports has issued before, but it remains more important than ever. Although Travelocity posted the highest percentage of lowest hotel rates, that percentage was not particularly significant. While Travelocity provided the lowest rates 29% of the time, it also failed to return the lowest rate 71% of the time. All the other sites performed even worse. If it's important to find the best travel rates and fares, you need to consult more than one site.
Always ensure that the rate you've found is available for immediate booking. The better sites will provide explanations of their booking policies.
Before booking a hotel room online, make sure you've determined the final rate. There may be additional charges, including federal, state, and local taxes; security and lodging fees; and booking or service fees from the hotel and/or the Web site.
Beware of potential bias. The screens on the leading independent travel sites are inundated with banner ads, pop-ups, pop-unders, and even listings of rates that are bought and paid for with hotel advertising and marketing dollars. Make sure you've examined all the choices before booking.
Never book a hotel room online until you've read and understood the cancellation policy. Many independent travel sites charge additional fees for changes and cancellations, in addition to fees levied by the hotel.
If you know the specific hotel you want to visit, find the branded site first. The branded hotel site may be maintained by either the chain or the property itself. Chances are good that you may find a lower rate there.