Mac keyboards are not designed for touch typists like me. There is no contour to the keys, they are flat and too large and make your hand move too far. They are also not sufficiently actuated, as Atwood points out in this post. They're made for people who hunt and peck and mash the keys using their biceps instead of their fingers. Since that's not me, I hate them. They have an "iffy" actuation instead of a decisive one.
They'll take my IBM Model M and Unicomp when they pry them from my cold, dead, fingers.
I used to be in your camp (started with the original Microswitch MIT-AI Lab keyboards decades ago, which are the best mechanical keyboards ever made, bar none), but I've become very fond of the thin Apple keyboards (and Apple laptop keyboard), which I find quite comfortable for fast typing.
The main thing is the short throw and light touch needed to produce letters with less finger movement and strain. (Just the opposite of what you posit with your biceps comment.)
When I'm peaking, I can hit around 80wpm (but not prolonged, at which point pain sets in), and I've got nothing but good things to say about the Mac chiclet keyboards.
I think the thing that makes me -not- hate them is that there's a solid banging sensation at the bottom of the pressing motion, as opposed to the mushy feel I've gotten from my Windows laptops in the past.