I am a long time Thinkpad owner, i had various models since the X200. This class is not about whichever machine gets more minutes of battery life or score 1% more in the bechmark. 12 hours are more than enough for a typical scenario with full working day at the customers without worrying about a charger and then put into docking station overnight, even with the drop in battery life in 2 years when the corporate gets you a new one.
The difference is that when you accidentaly drop a thinkpad, you just pick it up and go on with your work.
If you drop a Dell, it will break but they will fix or replace it NBD.
If you drop an HP, Asus, Acer or whatever piece of junk you imagine, you can throw it away and buy a new one.
Where thinkpads have metal joints and thick shell, others have think crappy thin plastic that will break at the first chance. My 15kg kid once stepped on the thinkpad LCD lid - no problems whatsoever. Try this with HP. ..