I spend way too much time in front of a computer, have done for years - and many years ago I began to develop problems with my wrists (presumably something like carpal tunnel syndrome although I never went to a doctor about it). I started using Microsoft Natural Keyboards and that seemed to solve it - but the keyboards are not small. These days I've moved on to a Kinesis Freestyle (the MS keyboards don't have the quality they used to have).
As a result, partly out of being so long used to big bent keyboards, and partly because of the "condition" - whatever it is - I have trouble with small or cramped keyboards, even laptops. I can use them for a short time but I quickly get uncomfortable - and I spend way to much time thinking about where the keys are to write very fast. So for now I am tied either to my desktop or to a system that will accept an external keyboard if I want to do any serious work. And, of course, needing a large external keyboard makes everything that much less portable.