Expedia released the 2010 edition of its Insiders' Select list May 4, which ranks the world's best hotels according to customers' reviews - revealing a somewhat different view of the world from travel review giant TripAdvisor.

A five-star hotel in Greece took the Insiders' Select top spot, with a South African guest house in second place of the 2,539 hotels featured. All in all, the site ranked properties from 1,022 cities using more than one million reviews submitted by its customers after completing a stay booked on its sites.

The Insiders' Select list is compiled as a similar consumer guide to TripAdvisor's Travelers' Choice list, which featured the top 719 properties based on traveler reviews back in January.

However, these lists could bring confusion for travelers, as none of the top ten hotels featured on the Insiders' Select list are featured as one of Tripadvisor's 719 top properties, and only half of them were rated as the top destination in their respective areas by TripAdvisor rankings.

One US hotel in the Expedia Insiders' Select global top ten didn't even make the top 30 hotels in its own city, let alone the world, according to TripAdvisor reviews. Conversely, Inn New York City, ranked by TripAdvisor Travelers' Choice as the most popular hotel in the US, doesn't appear anywhere on the lengthy Expedia list.

In fact, with a comparison of the top ten European and US hotels of both the Insiders' Select and Travelers' Choice awards revealing no common names whatsoever (despite TripAdvisor being owned by Expedia), which site can be trusted?

Although Expedia Insiders' Select includes properties from a list of some 123,000 and TripAdvisor claims over 500,000, a random sample test reveals many of the top establishments are listed on both sites.

Representatives for Expedia Insiders' Select says that it uses a "mathematical formula" to rank its properties, with over 1 million traveler reviews as the most influential factor. This approach is similarly adopted by Tripadvisor, although it appears to claim more traveler reviews - "millions" rather than "over one million."

From this point the lists begin to differ. Insiders' Select also incorporates value ratings to compile its rankings, comparing the average daily rates with those of similar properties and weighting the list based on its results.

It also takes into account the views of 400 Expedia "market managers," which are the company's liaison points with individual properties, to weight results, saying that they contribute "their insight and firsthand knowledge of their destination's best hotels."

These extra factors could account for the large discrepancy in results, but Insiders' Select has one strong point in its favor. Because it requires that a traveler must have booked through its service to be able to contribute a review, its system is less prone to manipulation than TripAdvisor's, where any registered user can post a review without needing to prove that they have ever stayed there.

This had led to criticism of the site from establishments and industry groups concerned at the power that the travel behemoth now wields over online booking.

For the moment, it's obvious that sorting through thousands of properties to find travelers' favorites is always going to present dangers, and neither TripAdvisor nor Expedia offers a perfect way of doing so.

Consumers can perhaps take some guidance from a 2009 survey by consumer analyst Nielsen. In answering, respondents stated that they placed significantly more value on the opinion of friends and family than that of consumer opinions posted online - proving that in the jungle of hotel reviews, there are still some opinions that count above all others.