Here is my experience from upgrading a W8 Pro to W8.1 Pro per means of (OEM) DVD. So, not downloaded - just bought. Notice that this is an 8.1 full version.
Brought back the OS in Normal Mode (so not Minimized).
Uninstalled the W7 shell provided with XXHighEnd. I did this while the W7 Shell was active (and Metro never started for the boot session).
After the Uninstall succeeded the W7 Shell was still active; from the StartButton the switch to the Metro Shell was still available. I clicked it and recall ending up in a black screen. No worries :
Use Ctrl-Shift-Esc to start TackManager, chose File from the menu, Run new task, and type Explorer. This now starts the Metro desktop.
Inserted the DVD and choose "Run setup" from the options popping up. From there all went automatically with the notice that right at the start the license key has to be entered. This could not be avoided (a normal - at east native W8 can avoid that).
At the end of the install set all my options (on provided questoins as usual) which comes down to not any (internet) interactions or whatever feedback anywhere.
This all ends with the suggestion that the system checks Internet for your blabla account (this was dealt with in a topic elsewhere), which in my situation (I think) it wanted to do because I had a LAN connection to my home network, but no Internet. This ends with something like "problem finding your account data" and the question whether I would like to continue with my local account. Of course I said Yes.
At the end all my programs settings were preserved (I ordered for that) and I started XXHighEnd.
This did not work.
From an internal XXHighEnd log file I could see that something had went odd and this is related to UAC settings (which I left at the for the OS inconcistent situation of the UAC at "Administrator Level" and while this was still so, my userid was not in the "role" of admins. I think this could have destroyed the whole upgrade, but it did not.
To solve it, move the UAC lider (which shows at the lowest position) up and down and Apply. Next start XXHighEnd again which now offers as usual to reboot because of self-set UAC settings. Do that, and now all works.
This was all.
All it now needs for the XXHighEnd version you have at this moment (say 0.9z-9b) is this :
Windows 8.1 - Error at Alt-X for XXHighEnd.
So, once you got acquainted with that it is a piece of cake to start the Desktop like this, especially because a second and next time "Explorer" is the default. Takes 5 seconds to do it, and in my view nothing to hold back starting Windows 8.1.
So yes, 8.1 activates the Metro Desktop and at this moment I see no downsides in it doing that. I mean, the way the normal Desktop (like W7) is dealt with is far more "devistating" but this already was so in W8 native. And how *that* influences SQ I don't even know. But never mind this; I will accept the consistent way of working easily and I see no downsides in the Metro desktop being there somewhere and which you will never see during your normal means of using XXHighEnd. Right after boot Yes; then you need to chose the normal Desktop one time.
Peter
PS: Small
: Since yesterday I have the Wallpaper (in Unattended) working for both W8 and W8.1 (which was the actual reason for trying out W8.1 in the first place - would it work there too ?).