[CaPPa]

As I live in Canada I refer to the British one as BB UK. The majority of people that I've talked to here didn't even know that there was a BB UK. I do not know whether it is well known outside of English speaking countries or the USA in general as I don't frequent many foreign websites/forums. It may be that the websites/forums that you visit are British and has American visitors who are hardcore fans, rather than it actually being well known across the pond.

As for Americans calling theirs 'BB USA', I think they just like to slap 'USA' on anything that they can.

One thing is certain though. BB UK is head and shoulders above any other version.

The big difference is the nomination/eviction process and that BB UK has a presenter who is animated, unlike BB USA that has a presenter who is robotic.