Actually, there IS a difference for McDonalds worldwide...
Having sampled McDonalds in the UK (home), america (slightly larger portions but otherwise the same), France (Fries are MUCh more salty), Germany, Poland and chekozlavakia (the latter 2 tasted weird, but I cant remember much about them except hte brugers had some interesting sauce in them that was like nothing in the UK)

Their the same meal but with slightly different touches...