I finally got the Microsoft Ergonomic Keyboard 4000 (sheesh! what a mouthful) and I do love it. So much so that I bought a second one for the office.
One thing I keep wishing with the MS keyboards, though, is to trade in the 'zoom' button for a scroll like the what you get with the mice. The customization software just doesn't offer such a feature. Well, of course, someone has found a way to 'hack' it.
Andy Atkinson has an article showing how to make such changes. The only addendum I would provide is that with my drivers, the file to run is "itype.exe" instead of "type32.exe"
Very handy... heck, what else can I change in here....