Because they're close enough to the regular keyboards, while offering both the split (match natural forearm angle) and the tilt (match natural forearm rotation) to better align natural wrist position.
I also like that they ditch the numeric keyboad, so I can put the Kensington ExpertMouse just to the right of the return key and not have to move my hand as far.
Comments
I'm partial to the GoldTouch keyboards:
http://www.goldtouch.com/p-133-goldtouch-for-mac-adjustable-...
Because they're close enough to the regular keyboards, while offering both the split (match natural forearm angle) and the tilt (match natural forearm rotation) to better align natural wrist position.
I also like that they ditch the numeric keyboad, so I can put the Kensington ExpertMouse just to the right of the return key and not have to move my hand as far.