One thing that particularly annoyed me about their en-gb vs en-us spelling example was "tonne" vs "ton". They are different!
I do wonder if America will _ever_ make the switch to the metric system. The French managed it in 1799; backwards Britain had mostly managed it by 1972; and yet working with US engineers means that I occasionally find myself converting units like slugs or "circular mils" into SI units for FEM modelling. Wolfram alpha is a godsend. I just really, really hate the US unit system with a passion!