US first release (MP-3 type) if it's the Japanese "USA Edition" (better rear wing tips IIRC) or you really want your Takara seekers to match it.

Japanese MP-11 if you want the better robot mode and accessories.

Hasbro MP-11 if you want poor QC, less deco.

For me, MP-11, but I can understand the appeal of the US first version in the window box.