Have you run the Windows 8 Consumer Preview? Are you aware of the very limited selection of apps they have at the moment? I would just wait for a fully supported and optimized tablet comes out, but if the money is burning a hole in your pocket, have at it... but remember you will in all likelihood have to purchase the final version of Windows 8 once it is released, so be prepared to add that cost to your analysis.
Acer Iconia W500. I have one right now with Windows 8 CP on it and runs everything with no issues. You can get some refurbs for real cheap too. To me the limited selection of apps is no big deal because Windows 8 runs all programs that windows 7 does and there is tons of windows programs.
I bought the MSI windpad 110W & upgraded the ssd to 128GB. Its now running Win 8 CP & I absolutely love it. I use it to impress my clients, presenting my 3D designs with Google Sketup. I have a VGA wireless (WiFi) connection to the LCD projector so that I could walk around the meeting room & up close to each audience to ask them what they would like to see more clearly. I then navigate & zoom in on the 3D design with my fingers including swinging the model 360 degrees without lag.
Reason I choose Windpad over W500 was the smooth touchscreen (glass)besides being thinner & lighter. But this is just a personal choice. Overall I think a Windows tablet is far more practical for me than an iPad or android pad ( which i have as well) as it can be used beyond just FB & checking emails.