This Evaluation Edition is a 90-day trial build of Windows 8 Enterprise. Essentially it provides you with everything you'd get in Windows 8 Professional, and includes a few additional high-end features: Windows To Go, DirectAccess, BranchCache and so on.
Beware, though - these trial builds will expire after 90 days. And you can't then revert to the previous version of Windows, or install another version over the evaluation copy (it has to be uninstalled, first). It's really just for testing, and once that's finished you'll need to remove it and start again with a fresh Windows installation.
There are smaller issues, too. Following the Download link will take you to a registration page where you must log in with your Microsoft account, and provide your name and email address. And you'll also need to activate the Enterprise edition online within 10 days of installation. (Although that's easy enough, as long as the system has an internet connection: Windows will prompt you on what to do and no product key is required.)
If none of these problems are a big deal for you, though - and you don't mind the 2.37GB download - then this is a great way to see exactly what Windows 8 has to offer. Especially if you install it within VirtualBox (or your virtualisation tool of choice), which will mean you'll be able to explore Microsoft's latest from a window on your Windows 7 desktop.
Note that the download link here will take you to the page where you'll need to login or register for a profile.
Forget the dubious RTM torrents, this is the best way to try out Windows 8. Just be sure you understand the restrictions before you download - the evaluation edition is really just for testing only.