Edit: the older Lenovo keyboards; reading more comments has informed me that Lenovo's using chiclet keyboards now too.
It's been almost 6 months now and, honestly, these days when I got back to do stuff on my T61 it's a world of difference. The W530's key presses are much more substantial and have a better feel; the quality of the keys seem much better; and the seemingly awkward placement of they keys (excluding the Print Screen key) seem highly justified to me now. And more importantly, the chiclet-style keys are grew on me almost immediately.
I've used the MBA and other chiclet-style keys and the main difference to note is that the Lenovo keys are slightly concave. This, to me, makes the keys feel less chiclet-y and more normal, though they do have the visually noticeable spaces between each key. Compared to the MBA, the MBA's flat keys just don't feel right and I feel make typing less accurate.
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!