Visited last year and loved the city. Have many good friends spread out across the UK as well, considering a year or two spent roaming the UK and calling London home for awhile.
I'm sure London and by extension the rest of England are nice to visit, but I want proper mountains and national parks, not the wussy ones we have here. I want proper beaches, and I want to be able to take advantage of my very strong English accent :)
So the UK is a great opportunity for commonwealth countries that can't get visas for the US.