The first issue is how to send the Ctrl-Alt-Del combination to the VM. Surely it's the same as it was in Virtual Server 2005 and Virtual PC 2007 - right-Alt-Del? Ah, but that would be logical! Nope, this time around the combination is Ctrl-Alt-End. (You can also use the Virtual Machine Connection window's toolbar or Action menu to send the Ctrl-Alt-Del sequence to the VM.)
Next user inteface issue is the mouse business. I assumed that installing the Integration Services software would give me the same freedom of mouse-movement I had under the earlier generation of products. Wrong was I. Once you click inside the VM, your mouse is stuck there. What kind of Integration Services are these? Yes, there's a helpful status bar message advising you to click Ctrl-Alt-Left Arrow to free the mouse from its VM confines. But isn't this a step back from the earlier products, which let you move the mouse in and out of the VM window at will? Maybe I'm missing something here. And, to be fair, I haven't yet built a VM within Hyper-V completely from scratch, although I'm not sure what difference that will make.