I'm definitely skewed towards Thinkpads, having carried one with me since '03 when I bought the first. My current laptop is an X1 carbon, and I can only say nice things about it. The only nitpick is that they messed the home/insert/end/Del key island.
I've heard very good reviews for the X1 Carbon. The only cons are: 1)weird keyboard layout 2)low-quality mousepad. Except for that the X1 Carbon seems to be a perfect Linux laptop. My friend's running Arch and it's working like a breeze.
I have an air and a t420 I've been planning on getting an x1 to replace the air. I've used the x1 and while the mouse pad feels extremely tacky to use I have a feeling its still going to work better and longer than the airs counterpart which is starting to do weird shit.
Lenovo often feels tacky if only because of their price constraints but what they offer for the price is usually an astonishingly solid build.
On the Linux compatibility side of things - most issues have work arounds on day one and full compat within a couple of months. I assume this is because of the heavy Linux following behind the think pad series.
It has a chicklet type keyboard, not the ones you find on previous thinkpads. I like it better than the old ones. Layout-wise, it has the weird layout of the home/insert island, and a stupid positioning of the print screen key. Other than that it's standard qwerty.
As for the trackpad, I'm not a good reviewer. I use the red trackpoint exclusively. My previous laptop (X61t) didn't even have a trackpad. Between the trackpoint and the touch screen, I don't ever use the trackpad.
My wife has a new Lenovo and I despise the stupid annoying keyboard layout because of all you mentioned AND the freaking position of the FN key and that function keys are not anymore function keys.
Want to close a window? Press Fn + Alt + Mute Microphone... WTF?!?!!
At least their ESC key is one of the biggest I've seen, so a big win for viers.
No problems whatsoever running Linux on it.