Choosing a Laptop, 2012 Edition

I have been using Lenovo laptops for more than seven years. They never failed me - not a single hardware fault or software instability in all those years. OK, not everything was great - I distinctly remember the R60 which had an atrociously bad screen - but apart from a few glitches here and there IBM come Lenovo delivered great quality again and again. And yet here I am ordering my first laptop from an entirely different manufacturer. How come?
Hardware