Here are some issues I have noted:
OS Info: Windows 8 Professional x64
First, the WB8 icon will not show in the tray area unless you go in and set it to Show Icon and Notifications on every boot. After rebooting it goes back to hidden all by itself.
Also, within WB8 itself the preview images on the left show the start buttons high up on the task bar on several skins even though they apply correctly, centered vertically when the skin is applied.
Using Windows 7 skins on Windows 8 produces several issues:
1. The show desktop image, even though it shows in Windows 7, does not show in Windows 8. This may be a forced OS issue though.
2. The start panel separator images are off in many skins even though they look fine in Windows 7, adjusting them using SKS in Windows 8 resolves the issue though.
3. The text margins used in a Windows 7 skin on the places panel do not display correctly on Windows 8, text has moved up considerably.
4. If you hover over an item in the programs panel that brings up a task list on the right side, the text color on the items in the task list is black and not as the text color assigned.
5. If you set an item in the places panel to be a popup menu instead of a link, the item mouse over image is not the same as it is in Windows 7, it is just a solid color.
6. The menu bar background (or toolbar image, not sure in Windows 8) in explorer windows (File, Computer, View, Etc.) is white and does not use the image supplied in Windows 7.
7. The log off button text (Shutdown) is not using the font assigned in Windows 7, and even changing it in SKS under Windows 8 does nothing at all.
8. Randomly an open window, could be any program or even explorer, will freeze and you cannot close it unless you right-click on the item in the task bar and close it there. For instance clicking on the close glyph does nothing except make the window appear in an inactive state and it becomes completely unresponsive unless you close it on the task bar.
9. The text and search image on the search bar on the start menu, even though centered vertically in Windows 7, is shifted downward a pixel or two in Windows 8.
I think these are all self-explanatory and do not require screenshots. Just check a few skins and you'll see.
More to come, I am sure. 
Oh, and by the way, checking "Email me when someone replies" at the bottom of a thread when posting does not work, no emails are being sent.
