I don't think there'd be any major differences, although the minor differences would be interesting to see. Books (at least those of any quality) seem to travel much better than TV, and a bit better than film... I find it much easier to read American English than to listen to American English; and the first world-class NZ SF or fantasy writer that I can think of (Phillip Mann) seems to get as much attention worldwide as any other writer in English of comparable quality (reasonably high) and output (rather low).