Very funny coincidence: Exactly one year after my devastating test of Windows 8 on the EEE PC 1015PN ( here) I tried Windows 8 again - 8.1 to be frankly.
After booting from the DVD, I entered my Key and choose to keep my data and such - an Upgrade Installation. Sadly, installer told me that I needed to choose that after booting into Windows 7 and starting the installation process there. Well, I did. But I only could choose to keep my data - not my programs(!). Sad, but - well. So - if you want to install and keep your stuff: Try to install Windows 8 first and then upgrade to Windows 8.1! I made an backup (just in any case - last time showed me the importance again...) and started with the installation. I took quite a while, but in the end it succeded. This time (and maybe because I changed my Wifi/Bluetooth Card from Azure for an Intel ABGN/WiMax Card?!) - I got none problems with Wifi. Working excellent from the first moment on.
I even got Optimus working by following my own tutorial here, by using the mentioned Versions.
Concerning other drivers and tools: I installed successfully the Optimus Tool, Capshook Driver - all by using the Windows 7 Compability Mode. ( I needed to use that as well on the Optimus Driver installation!)
Regarding - especially - the AHCI Drivers (Hotkey Service) and the SuperHybridEngine Tool - well: First of them gives REAL problems. It won't work and always remind to install an working AHCI Driver. Luckily, some guys found out an way to change that: Just install these tools from an newer ASUS EEE PC - the Asus 1225B. And that does work! Link: Source, Drivers - Good thing: Without the blocking AHCI Drivers Optimus does work correctly. But fixing ACPI is not enough. You need to setup the right Touchpad Driver!
About the Touchpad? Well - you need another Hack for Windows 8: Go with these. I chose the Elantech Touchpad driver Version v.10.6.6.0.
What I really changed? Well I did some normal stuff like disabeling the User Rights Control Thingy - as well as I changed the Resolution of the Display with this little hack. That got the Metro Apps working and my display from 1024x600 to 1152x864. Ok, it is not very crispy - but really gives more usability. ( Just watch for the "Display1_DownScalingSupported" setting in the registry and enable it )
To get back your classic Start Menu Button - use: http://www.classicshell.net/
Ok, that was a lot of stuff and I am curious to see how Windows 8.1 will perform in "real life". Well, I am off to installing some more tools and such.