After you've selected the locations you'd like to compare, the website creates a grid that lists the class of vehicle (compact, SUV, etc.) each location offers and the price you'd pay for a car from each class.
The website highlights the lowest available price for each class among the locations you've chosen, and clicking on the price for a given class and location allows you to see the brand and model that location offers. But while the website will indicate that you may receive, say, a Ford Edge if you're looking for a standard SUV, it also notes that you may receive a similar car instead.
This page also shows you the perks each location offers for each class, such as unlimited mileage and the ability to register an additional driver for free.