I use the MS Natural Ergonomic Desktop 7000 at work and it has definitely saved my wrists. I started to experience significant pain after long periods of coding to the point where it was keeping me up at night. After switching to the MS keyboard/mouse the pain simply went away.
Two of my biggest gripes with that model are the function keys and the materials used in the mouse. On the 7K, the function keys default to media keys instead of the F1-F12 that I use all the time! I'd rather not have media keys on my keyboard at all, though I know some people like them. Having a simple switch to choose the default behavior sounds like a perfectly reasonable compromise.
As for the mouse, the 7K has a clear plastic gel layer where the thumb rests. It's great at first, but over time, it turns yellow and disgusting from skin oils and then begins to peel, giving a rather unappealing texture. Judging by the photos here, they've eliminated that in this model.
I must admit to being very tempted to replace my 7K with this for those issues alone. The detachable number pad seems like a neat feature, though I'm not sure how it would work for me in practice, as I am a heavy number pad user. I'll have to see a photo of it.
I'm curious about that Windows key on the mouse. Can it be reassigned?