I always bought clarks, but it depends on who you get sometimes how well they are fitted - you need to use your own judgment too. I think some of the european shoes brands are better quality, but you have to be confident that you know your childs foot shape properly. Ebay is good for buying up excessstock, but again, you have to be careful as sometimes the same size (and width) shoe in different styles is not actually the same size!!!
The last time I went when my son needed new trainers, they wouldn't sell me any as they did not have anything in his size in a narrow fitting - they told me to just go to a sports shop. Didn't find that particularly helpfull as at least the clarks one would have been closer to a correct fitting and the sports shop ones could have been way off! Boiught him clarks ones from ebay in the end!