In the beginning, you called an airline or travel agent when you wanted to book a trip. But if you’ve done any traveling at all within the last 15 years, you’ve probably come across a fare aggregator or metasearch site. Hundreds of perfectly legitimate ones exist; you’ve undoubtedly heard of Expedia, Priceline and Hotwire, to name three. Does it matter which site you use, or are they all basically the same?

These online travel agencies, or O.T.A.s, and search sites scrape data from other sources, reorganize it and present it to you, the user. The two proverbial 800-pound gorillas in the travel world are Expedia Inc. and the Priceline Group. Together, they have a hand in most of the major travel booking sites. I ran through various scenarios — purchasing a flight, a hotel room and a flight, hotel and car package — with the aid of a sampling of those sites: Travelocity (owned by Expedia), Kayak (owned by Priceline) and the newish kid on the block, Hipmunk. I also searched directly with airline and hotel sites. I admit that I went into this informal study expecting prices and options to be more or less the same from site to site. Let’s just say I was surprised by how mistaken I was.

Features

Let’s highlight a few features of the sites before getting into the nitty-gritty of travel details. Travelocity offers some nice options for travelers, including a $50 credit and refund of the difference if you can find a cheaper price on a flight, rental car or cruise within 24 hours of booking. It also featured some surprisingly useful travel articles in its “Get Inspired” section, including write-ups on Spanish sparkling wines and ideas for family-friendly locales in Ireland.

Kayak is more search engine than travel agent, and its focus seems to have shifted away from flights (more on that later): The site’s default search offering now involves hotels. It also allows you to connect, in most cases, directly to the service provider. If you search for a Hyatt hotel, Kayak will encourage you to book through Priceline, but will also send you to the Hyatt website. Some of its best features are its price predictor tool, which advises you to wait or pull the trigger on a purchase, and its alerts, which will track airfares and hotel prices over time; an email alert option will notify you about price changes and recommend that you buy or wait.