I've had the Windows 8 Preview for a couple weeks now. I really hated that the start button was missing at first but have gotten used to it. TIP: if you hover in bottom left corner (where the start button used to be) the apps window will pop up for you to click on. The apps window is pretty cool, a lot of room to organize your files and applications.
Over all, I am not impressed by Windows 8. Seems like a lot of cosmetic touch ups and a few new features rather than a brand new OS.