This is a content-free comment. You claim ThinkPads have better ergonomics, but you say nothing about why. You say they are more robust (more robust than a solid aluminum shell? Not in my experience), but you don't back it up. You claim better performance and say something vague about RAM, which is similarly unsubstantiated.
The IBM has a vastly inferior, smaller, less responsive trackpad, inferior display, inferior overall fit and finish of the case, inferior trackpad buttons.
In my list, generally preferring Thinkpad over Mac:
Better keyboard feel and layout. Especially if you're used to PC/Unix keyboards.
Trackpoint. I vastly prefer this to a trackpad (and generally disable trackpads in BIOS).
Cooling/airflow. Mac's sealed design is nice, Lenovo's gets the heat out (and the dust in, sigh).
Thinklight.
To Mac's benefit:
Magnetic breakaway power connector. Sheer genius.
Illuminated keyboard. Kind of neat.
CD slot (not on Airs, obviously). I'm always accidentally opening my CD drive on my Thinkpad. Some way to lock the damned thing would be nice.
Displays -- I've been consistently impressed by the brightness of Apple displays, if not the aspect ratios (I prefer Thinkpads generally here, though they're converging on Apple's standards).
And in 10+ years of lugging Thinkpads around, I've had few if any hardware/robustness issues. One screen that pixilated badly after a fall onto the street in my satchel, replaced by IBM. Otherwise, nada.
The IBM has a vastly inferior, smaller, less responsive trackpad, inferior display, inferior overall fit and finish of the case, inferior trackpad buttons.
You'll have to do better than this.