Probably the most comprehensive preview I've noticed
Snips from page 4 of 19 (only part of the conclusions since I'd rather not rip other peoples content) -
For most, the number one fear with Windows 8 and with Metro is that Microsoft is sacrificing current desktop and laptop users of Windows in an effort to chase the tablet market. Some may disagree with me, but I don’t think this is true. The Start menu is gone, but consider this: the best thing that Microsoft did to the Start menu came in Vista, when the new integrated search made it so that you didn’t actually have to go digging through folders and sub-folders. Not only is that search functionality alive and well in Windows 8, but the problem of folders and subfolders that it was created to avoid is also gone.
Yes, Metro is very different from what came before, and yes, Metro was clearly designed with touch in mind, but once you learn its tricks (and especially once you’ve got the new keyboard shortcuts dedicated to memory) it acquits itself as a flexible and powerful user interface. Even if you’re on a massive 2560x1440 display with multiple monitors and never, ever touch the Windows Store or a Metro app, the Start screen serves as a much more configurable and useful application launcher than the tiny Start menu ever was.
Snips from page 19 -
The other problem Windows 8 is going to have is that, while it offers some nice under-the-hood updates, and while Metro is much more usable with a mouse and keyboard than some pessimists will lead you to believe, it’s not the essential upgrade for PCs that Windows 7 was. Thanks in part to the user-facing and under-the-hood improvements in Windows 7, desktops and laptops don’t need a new operating system like they did three years ago when their only options were the aging XP, the flawed Vista, or the alien landscape of Linux.
If you’re reading this, the chances are good that you’re a technology enthusiast with a decent system, and you’re the ones to whom Windows 8’s under-the-hood enhancements will appeal the most. Give the preview a test drive, evaluate whether you’ll use the new features, and give Metro a fair shake—like it or not, it’s the future of the platform, and it’s well-implemented here. If you’re happy with Windows 7, though, this isn’t the must-have upgrade that its predecessor was, and Microsoft’s long-term support cycle—mainstream support until 2015, extended support until 2020—means that you’ll still get significant software updates (new DirectX and IE versions and a handful of other backported features) for awhile and security updates for even longer. You’ve got time to wait for Windows 9.