I've fancied items from TV shopping channels from time to time but have then looked up the item on the internet and got the company address. I prefer to deal directly when I can. I think it can save hassle. I wouldn't buy jewellery on QVC but that's just me.
OH has bought the odd kitchen thing from QVC they've always been good quality and they do have a 30 day money back guarantee if you change your mind. I don't buy anything from tv shopping channels though , I like to touch and see what I'm buying..
Nonu, my friend used to enjoy buying on QVC, and I think she still does occasionally. However, when I was in my wee local jeweller's the other week (he's a goldsmith and a jewellery designer/maker), I saw that he'd put a notice up saying any alterations to items bought from QVC were done at owner's risk, due to the often poor quality of stones, etc.