This new apple keyboard is substantially smaller than the older G4-style keyboard, and probably a bit smaller than the G5/x86 keyboard. Unlike the G5/x86 keyboard, it does not feel cramped. The keys appear spread out due to the shape and shallow depth of the keys (previous keyboards had trapezoidal keys, when viewed from the side or front), but typing is comfortable and easy.
One word of warning, this keyboard does not appear to work with my IOGear GCS632U KVM. Normally, keyboards with LED backlighting have trouble with unpowered USB KVM switches. This apple keyboard appears to just be a simple keyboard + 2 port hub, just like the last few apple keyboards, so I'm a little surprised that it doesn't work.
Edit - Since this keyboard is a USB 2.0 device, the KVM issue may simply be that the IOGear KVM doesn't speak USB 2.0.
The easy workaround is to use Synergy, an excellent free software switch.
In conclusion - I like the feel of this keyboard well enough that I'll keep it and look for a new KVM rather than the other way around.
Update: two weeks later, I still like this keyboard. Synergy is far more convenient than a hardware switch, so this keyboard deserves 5 out of 5 stars.