The last time I used a Thinkpad was a couple of years ago, when I was working off of a friend's. I don't remember liking it much; I think this one is better, but to be entirely honest, that was ~2 years ago, so don't put much weight into that.
The main thing that distinguishes this keyboard from Apple's is that the keys aren't as flat - I'm used to tactile and auditory feedback on the Das Keyboard, and while neither Apple's nor Dell's keyboards provide this, having the indentations makes it slightly easier to type quickly (notice how the Das keyboards all have slight indendations too).
Also, the BIGGEST problem with Apple's keyboards for me is the 200ms delay hardcoded in the firmware for the Caps Lock key. I rebind Caps_Lock -> Escape for vim, and this frustrates me to no end.
At the end of the day, neither you nor I are ever going to be happy with any laptop keyboard, since they're all non-mechanical, but I think this as good as we're going to get.
 I have the "silent" (ie, still-audible) one at work and the regular (loud) one at home.
That should make a big difference; I'm amazed at the number of typos I make when I'm using a mac. Thanks!