Thanks for reviving this thread, f0dder. I'm interested, but am wondering about the resource "hit" under Vista?
My laptop runs Vista64, and it uses... dunno, ~20MB or so of private bytes. On my Win7-64 workstation (still running a post-RC beta, haven't upgraded to RTM from school's MSDNAA yet) it's weighing around the same (and running 100% smooth, thanks to the "somewhat more powerful"
GPU) - around 10meg non-shared working set, that's not
bad at all either.
As for CPU toll, I let a DivX movie play back in Windows Media Player on my laptop, and kept the System Information window from Process Explorer open as well. I couldn't tell the difference in the CPU usage chart from having the Switcher exposé mode running or not, even when flipping rapidly between windows in the F2 mode - testing now on my quadcore workstation, keeping Properties->Performance open and doing the same hits in at around 0% CPU usage for the Switcher process, and some hardly noticeable spikes on the procmon SysInfo CPU chart, as expected caused by the dwm.exe process. Those spikes were around 5% or so when doing "normal rapid" flipping, and up to 15% when keeping an arrow key pressed.
Haven't checked if dwm.exe memory consumption goes up when using switcher, but I expect it won't - it's already responsible for keeping the window content of the applications.
In other words: pretty negligible resource consumption. I should test if I get different memory consumption with varying number of open Windows - and it's worth testing the difference between Win7 and Vista as well, since Win7 (if running with a new WDDM driver (1.1 as opposed to Vista 1.0, iirc)) keeps windows on GPU memory rather than system memory.
PS: I expect that pre-Vista compatible exposé clones will be worse wrt. resource consumption - they need to basically take screenshots of all your open Windows in order to work, which takes some memory. And for "live" previews, they need to keep taking screenshots (the faster the "smoother") - this takes up CPU cycles.