Dual-head is cool, but annoyingly implemented. Win2K (or perhaps the Matrox drivers, I'm not sure) does not treat the two screens as separate, but just spreads everything out so that I have a screen resolution of 2560x1024. This is neat in theory, but in practice it means that when you maximise a window it takes up both windows, the systray in the taskbar appears on the secondary screen, and all sorts of transient windows (such as alt-tab) appear in the "middle" of the screen, unreadably split between the two monitors. I'd much rather have both monitors be a "desktop" in their own right.
I also discovered that my 17" monitor (the second one) is stuffed. Even if I shrink the horizontal stretch to the narrowest possible setting, the picture is too big for the screen. This is regardless of what computer it's plugged into or what resolution I've chosen. Not happy.
(Update) I downloaded more recent drivers for the dual-head. They work properly. Now all I have to do is get the damn second monitor fixed.