I now have 4 Kinesis Advantage (2 old ones with AT connectors and 2 new USB ones). I use them in Dvorak mode in combination with a footswitch for shift/control to avoid having to strain with combinations, and I love them. They are totally remappable, mac<->pc switchable, qwerty<->dworak switchable, etc. If you have very short pinkies (like me) the pinky areas are less comfortable, but I've remapped the symbols on the outer rows to ctrl-number so I don't have to stretch my pinkies.

The only thing I miss is the ability to save the layout to a file on the computer like I could on my Fingerworks gesture keyboard.