It seems to me that a lot of these companies now do very good deals it terms of spec for your money, but they are not too keen on after sales support. I recently had a long chat with Time computers - the spec was very good, they even offered to throw in extras as soon as I appeared to be hesitating but I wasn't very impressed by their potential after sales service. Which is why I generally now buy component parts and build my own.
This site may be helpful for opinions - although it may only be the extrmists who contribute:
http://www.dooyoo.co.uk/product/128654.html