I just bought one last week. I use it several hours a day for surfing, coding, watching DVDs and playing games. So far I haven't faced any problems. 

Mind telling me what negative comments you've heard about it? So that I can be ready if something breaks.

I see. I haven't heard much about their battery problems. Then again, my Vaio is still new. After a few months if I do encounter heating problems, I'll post back here.

But hopefully not. 

Personally, i don't think sony Vaio are not stable, if it is true that Sony VAIO is not stable, then their market value wont be so high in the market compared to others.
Furthermore, VAIO is not only well known with its performance in local, but also in oversea.
Other than that, with 10 years of R & D in computing line, i dont think it is impossible for them to come out with a great performance laptop.
For you guys information, lately, Sony VAIO is the first brand which comes out with Penryn processor.
An addition, SONY is the biggest distributor in battery cells to most of the brand in Malaysia. In this case, if let's say VAIO battery got problem, then others confirm got the same problem too. Meaning because all of them are using the same technology in their battery cells.
Regarding about the battery heating problems, i don't think it is true. For you guys information, there are alot of retails shop in Malaysia in which their VAIO display unit were displayed with battery attached to it. Just imagine, they on their VAIO for whole day also no problem, it should be no problem to you right ? =)
Furthermore, VAIO laptop even you on it for whole day, the bottom part wont get heat easily compared to other brand.
Thats why you can see during PC fair, other brands seller will definitely put one cooling pad underneath their laptop and make it as selling point inwhich the cooling pad are given for free with that particular purchase. This is because, their laptop will get heated easily after on it for around 20-30 minutes.
QUOTE from SUkun,
"Sometimes is just the person on his/her knowledge in computing stuff that really matters."
It's depands on you want to drive a Ferrari or Kancil =)
Its all about the branding.