It doesn't matter, there is no good way to have an even playing field for both sides. Until the Atlantic Ocean Server gets hosted ping will always destroy any attempt at comparison.
I will say that given the greater population in EU there is likely a greater range, and with more players at the 'top' there will be more high tier competition, thus better 'elite' players... but really we're probably about the same on both sides.
Of course NA has American exceptionalism, so NA auto-win.
ANYWAYS
I'm actually surprised more EU builds aren't strength heavy. With higher pop in battles and (allegedly) more ranged spam & team wound potential you would think having that extra hp and easier chance to 2 shot people strength would be ideal, while the more duel-centric builds would be preferred in NA.