I had RSI. Got over it, but still found mechanical keyboards uncomfortable.

For some reason, I find the MacBook air 13 inch keyboard to be the most comfortable I've ever used.

I don't know why. Part of it may be the low height from the ground, and part is the great trackpad. (I tried the magic mouse and hurt my arm)

I expect other people have different opinions of the air's keyboard. The point is that I don't think there is any one keyboard that works best for everyone.