Maximum PC have a review of Windows 7 that provides a good basis for users that haven't tried the Beta/RC editions. Of more interest to enthusiasts is the inclusion of over 80 benchmarks comparing W7 to Vista and XP:
http://www.maximumpc.com/article/reviews/windows_7_review
You can check out the article here:Whether you’re coming from XP or Vista, Windows 7 offers a massive leap forward in usability, security, and support for new hardware and technology, especially for enthusiasts and power users. For anyone who regularly keeps many windows open at once time, the new Taskbar is worth the price of admission alone. For XP users, the security improvements are equally worthy of praise, while Vista users will be thrilled with the much improved, much less annoying UAC. Add in support for new hardware technologies, more new features, and the kernel improvements that should allow you to get more from your multi-core CPU, and Windows 7 becomes a tidy, compelling package to all Windows users.
Best of all, the new OS simply feels faster than Vista or even XP. As one editor said after a session testing the OS, it’s the best of both worlds—the user interface speed of XP and the features and security of Vista and more. That’s something to be lauded.
http://www.maximumpc.com/article/reviews/windows_7_review