Discussion: Who has better fantasy, UK or US?

A few months ago I got into a discussion with someone on Twitter about the quality of fantasy/sci fi in the UK and US. Basically, this individual’s perspective was that, “America has all the good musicians. The UK has all the good fantasy authors.” While I don’t know if I agree or disagree, or if I even think it matters, it’s surprising how often a discussion simliar to this pops up on Twitter, or blog posts all over. 
I thought it would be interesting to see if my readers agree or disagree with what I quoted above. Do you think the UK pumps out higher quality fantasy/sci fi than the US? Do you have any theories as to why that may/may not be the case? Or, do you fit in more with the “who cares” camp?