I've been using the icekey for quite some time now and I love it. It feels pretty much like my PowerBook (aluminum) keyboard, which I also love. Basically, if you like notebook keyboards with short key travel, you'll probably like it. One problem is that the special keys like volume require installing software on your Mac and don't work on Windows (I liked the keyboard enough that I bought two -- one to use with my Windows gaming computer).
I'm pretty tempted by the new Apple keyboards myself, though.