Not just Thinkpad either, but T series, T is the mainstay for businesses (certainly by volume), that shows a lot of trust, E lines are entry (and largely to be

Not just Thinkpad either, but T series, T is the mainstay for businesses (certainly by volume), that shows a lot of trust, E lines are entry (and largely to be avoided if you can), X is thin/light and P is workstation class (Xeon's and Quadro type stuff) - Though the newer T's aren't that much thicker/heavier than the earlier X's so the lines are blurry.