Looks quite nice if you ask me. Looks like they're going along the same approach as Wii Play whilst combining their approach to the Wii Sports cover at the same time. I think it could be a bit better (seeing the white at the top is a bit of an offset) but it's not bad.
As for the European shot, it looks really nice. I actually pictured the boxart being something where it would be a top-down view of the island with various Mii's participating in different sports but this is even better! Once again, Europe gets a stronger boxart!