As long as you ignore the sales staff PC World isn't all bad. It used to be that all the stock was vastly over priced, but nowadays a lot of it is more competitively priced.
Of course when I know I need to buy something from them I go online and get their "collect @ store" price, which usually matches or comes very close to the best online price.
I have also found their support people surprisingly helpful. I needed screws to mount a laptop drive one Sunday and couldn't find anything at home to fit. I happened to be near PCWorld so I popped in and asked at the support desk, sure enough they came out with a collection of various screws and let me take what I wanted.
When something breaks on a Sunday and you need to fix it then and there they are the only place open...
Helpfully they also have some Dell machines in store now, which meant when my mother finally decided to join the PC age I could take her to have a look at the Dell laptop I was suggesting she should buy.
But yes, the sales staff are hopeless. Thankfully the ones in the Norwich branch the other week got the message fairly quickly that we really didn't need any help