The thing with computers in my experience is everyone has an opinion and at the end the day thats the way life is.
I have an an opinion that i wouldnt buy a laptop/computer from a supermarket (Tesco's) just the same as i wouldnt buy my groceries from PC World if they started doing them.
PCW has a history as poor but thats the staff not knowing enough of what they talk about, i know one my local stores employ people i would trust to fix a computer and advise on the purchase of one as i taught them what they know when they was students in the college i used to work at
I have had good and bad experiences with several makes and models of computers/laptops
Acer, Dell, Toshiba, Sony and Compaq
If i was going to buy the only things i would avoid at all cost is the likes of E-machine and relativly cheap brands
best advice is look around and read reviews place i have used and had no issues with aftersales are
and my local trade supplier there are a few more but i havent bought laptops/computers from them so not adding.
Dell again are mixed bag o reviews, but like anything they tend to be the really cheap machines that i have ever had issues with and not the decent machines.
I am selling one of the old ones that has been going for years only issue ever is the odd re-install of the operating system and more recently the need to add a new keyboard
and no i am not suggesting that before anyone says using as example of reliability
Go look at Dell but dont make it your only choice is what i was saying i know a few people who bought the vostro from them and are very happy with it.
read all the user reviews on what you pick before you buy though aswell