As it stands, I'm unimpressed. The Metro UI apps have pretty shitty backgrounding, the Metro IE doesn't support Add-ons (no Flash/Silverlight/etc), and the ARM port of Windows 8 doesn't support x86 apps, all of the above citing reasons that ultimately end in "Hurr, saving battery life :B"
The lead developer for Windows boasted about how Windows 8 would make it so you didn't have to switch devices to carry out simple tasks, yet they bar x86 apps from the ARM version? Basically, you have to switch back to your desktop computer to run programs that you need. Why? Because they felt running compatibility for x86 programs sucked up too much juice from your battery. By that logic my laptop should be running Android. 8| Also, if you're going to restrict tablet versions of Windows 8 from running how they should be run, then why are they so hellbent on making all of Windows 8 a tablet experience? If the ARM version is basically pointless, making tablets useless, then what's the point of the tablet UI at all? Windows 8 shoves this tablet UI over the desktop environment, like shoving Media Center as your startup screen. The tablet UI is, despite what Microsoft claims, a horrible experience when used with a mouse and keyboard.
Furthermore, IE's choice to bar addon-ons makes what should be an inclusive experience into a very discouraging experience. No Netflix, no Youtube (unless run as HTML 5), etc. Basically, for that level of shitty browsing I might as well get an iPad. The desktop version DOES, however, support Addons. Still, though, why bar it from the Metro UI version? Flash is still relevant. GET OVER IT.
Microsoft is utterly fragmenting Windows with a lot of their choices. I get that it's an alpha and nothing is set in stone, but these are my criticisms for how it stands.