I used to have a samsung tv and ended up taking it back in the end. I found it very poor for quality and the remote and UI very difficult to live with. I usually stay away from sony tv's as they can sometime also be over complicated, however the new sony LED I have is nothing short of fantastic!!
Defo take a look at sony as their new ones are quality. My tip would be dont go cheap to get something bigger.... you will alway regret when you see problems with the screen, and wish you had gone with quality. 
Yes but if £400 is all he has then he can still get a decent tv for that... Yes LED will be better but your samsung would have been lcd yes? You cant compare the 2 Plus depends on the model of the samsung you bought might have been a lower end model... You can buy a samsung LED for £550 40" and the picture is amazing... With regards Sony LED tv's Yes they are good But even there screens are made by Samsung.....
My samsug wasnt LED, but at the time it was one of the best tv's out which I paid alot of moeny for. When I now compare my sony to the samsungs out there for a similar price you probably geta little more for your money with the samsungs. My point was dont go for bigger = better. Just go for the one with best picture quality and useable UI.
I find that the sony has the better picture and UI, but then I really only use mine for gaming. It really depends what you want it for then look for which suits you better. What suits one person on a forum may not suit another for their purpose. etto
