I assume the reason they're on a ThinkPad/Lenovo is that there is a well-deserved reputation there for running Linux well.

I recently picked up one of the new Toshiba Portege models to run Linux, and stock Ubuntu is giving me flashbacks to the circa-1999 Linux experience -- it doesn't detect when a monitor appears over HDMI, randomly will run up to 100% and freeze (kernel patch coming soon!), power management settings seem basically ignored with the display dimming when that is both disabled and I'm typing... and the worst part? Mentioned it to the local department Linux people, and they just said, "oh, yeah, you should've bought Thinkpad."