There are a few reasons I prefer my T430s to my MBP, and would probably also prefer an X1 Carbon to a MBA:

* Trackpoint!

* Keyboard feel. Even the chiclet ThinkPad keypads still have "IT" for me.

* No more fn-key chording needed for Home, End, Delete, Page Up, Page Down.

Plus a non-technical, possibly silly, reason of "it's not what everyone else and their mum has." I also like the looks more (black is the new black!), though on that I realize I'm in a minority (I did love the rounded original MBAs, however).

On the other hand, my MBP's screen has much better colors than the T430s's. :(

BTW I have moved from t420 to x220 (smaller display, but IPS) and, having quickly adapted to a bit less real estate, could not be happier. x220 IPS screen blows away everything save for retina.

And yes, no proper laptop should ever be sold without a trackpoint and a proper keyboard! :)

> * Keyboard feel. Even the chiclet ThinkPad keypads still have "IT" for me.

Having both a standalone, "classic" Thinkpad keyboard and a Thinkpad with the chiclet keyboard, I find the resistance on the chiclet much more satisfying. Best keyboard I have used so far.

If [your favorite OS] is Linux, the fact that doing so roughly halves your battery life (or, more precisely, nearly doubles the idle power draw) is certainly a factor — it's a lot of why I'm not running Linux on my (4,2 — 2011 13") Air. I have no data as to how battery life fares under Windows of any version.

EDIT: For clarification on power consumption, the best idle draw I've seen anyone get in my moderately extensive research into running Linux on this machine is 7W; under OSX, it's fairly easy to get down to 4W.

Windows battery life tends to be really good because the manufacturer/vendor has put a lot of effort into optimizing the drivers. Which is also the only reason Linux has more power draw.

But Windows is a terrible environment for developing almost anything other than Windows-only stuff like .NET and PowerShell

How about games, audio apps, 3d packages?