1. Metro is nice, but the apps are still missing close buttons. If you want to go Metro-less, you can, but....
a. Expect some "Microsoft Confidential" notice to pop up from hereon.
b. No more fancy Task Manager.
c. No more fancy copy dialog.
d. No ribbon dialogs in Explorer.
2. Microsoft appears to have put their own anti-virus software in it. Pings the CPU load as I've seen it do in the past: hope we can still put Avast on it, or something.
3. Command prompt (cmd.exe) appears to not be admin-default, even with the user set as an administrator, and User Access Control turned off. Right-click cmd.exe to "run as admin". I'll have to check this further to see if UAC disables correctly or not across my setups.
4. I use some netsh tweaks for performance improvement: running my normal script triggered some errors; it looks like Microsoft might be adding support for DCTCP (it shows up as a congestion control option, along with CTCP). Example command to try: netsh interface tcp set supplemental internet
5. ActiveX controls that worked on IE8, and broke in IE9 (security cameras, etc), are still broken in non-Metro IE10 (you can use either with the default install).
6. It auto-installs network printers, and puts them in your Device Manager.
7. Application quirks: TightVNC gets an "Error 5" on its admin console; RDTabs works, but there's an additional permissions prompt from Windows for web-based something.