If you buy Windows 8, you will miss these features:
– Make available offline
– RDP into the machine
Windows 8 to Windows 8 Pro upgrade ($99) will not upgrade your system to Windows 8.1. That step is free and heavily pushed by Microsoft. The reason is that you ONLY can login with Microsoft account. No more local accounts are allowed.
Skype (in Apps) already have this annoying feature. You can bypass by installing a Desktop version.