My little bit of anecdotal evidence:
I spoil myself as I've had my own business in tech and have replaced my laptop every 2 years for the past 16 years or so. All this time I've Dells simply because 1. I liked the aesthetic of the their business-class machines, 2) they were always reasonably priced, 3. they were completely configurable, 4. they were very quick to outfit their top-end machine with the latest and greatest tech. Usually at the end of 2 years I was itching to get my new machine.
Last laptop I bought, however, was a Lenovo W510. I got it nearly 3 years ago. I have no desire to replace it any time soon. Admittedly, I did upgrade to a SSD after having it for a year, and that give it a great performance boost, but more important than the performance is the construction and the feel... I'm very sloppy about how I care for my stuff, I don't take good care of things at all. This laptop still feels like the day I got it, and something about the matte finish of the case makes it even look like the day I got it. The cover clicks closed nice and tight, the hinges open slow and smooth, the keyboard feels solid - better than any other keyboard I've used. The screen is IPS and very bright.
My biggest gripe about Lenovo (and it's really a gripe with most of the big laptop makers) is that they've moved to putting numeric keypads on almost every business model. I HATE having my main keyboard being off-center from the laptop screen! I really wish they'd offer different keyboard options in the same way they offer different screen options.
Cheers,
CList