I would say that Linux isn't really mentioned much here for the same reason you don't get "Poodle Dog Forums" members raving on about the latest E63 vs. M5 review in AMS or whatever - it's not their area of expertise.  Granted, and I'm speculating a bit, but computers and cars are probably more likely to cross as areas of interest than poodles and cars, but you get the idea.  Linux is a specialist operating system for what really are special circumstances.
Anyhow, as for laptops, yeah, I've heard of those manufacturers like Clevo and Twinhead.  Some are better than others.  Not so long ago Asus was probably in the same boat, and now they've gotten to a higher level (IMO).  I think Asus once (or still does?) make laptops for either Sony or Apple themselves.  However, I'd rather buy a laptop with a little better reputation - it's a lot harder to rectify a dodgy laptop than it is to rectify a dodgy desktop, where I know I can unscrew the thing and replace anything I want.  Laptops also come with integral parts - you can't swap out the chassis or the keyboard, for example, which are things that are difficult to evaluate without actual use.  Therefore, I go with the good ol' "they've been doing it long enough" or "it costs more therefore it's better" method of trying to get some sort of quality, valid basis or not.
Anyhow, these days my upgrade requirements for a PC have changed a lot.  I once went for good gaming value for money, now I don't have much time for that and go for lower specs and lower money.  That said, people underestimate the hard drive component of the computers - really, that's the most important and valuable component of the whole computer.  Not worth much empty, once with your info on it, it's priceless.  Hard drive errors or data-related human errors are generally uncommon, but they do happen.  I guess that most people just don't know what they've got 'til it's gone.