So the differences between this and the Japanese version
So both sets of figures have an almost neon green as their base colour, dark grey treads, and light grey paint apps on Demolishor. The differences are -
Paint Apps: The Hasbro release has a dirt wash look on the figures, but that's it.
The Japanese release has purple on the figures, red for the eyes, and painted dark grey details on the figures, none of which are present on the Hasbro release. Also the Japanese release has a metallic paint wash effect on the combined mode face and mechanical detail on the neck painted in red, both lacking in the Hasbro release.
The light grey is on the same places on both sets.
Windshields: Hasbro release has them in a dark purple (almost grey it's that dark).
Japanese version has them in a more traditional constructicon purple.
Faction Symbol: On the Hasbro release it's the same purple as the windshields.
On the Japanese release they're a slightly darker purple than used elsewhere on the figures, except on Mixmaster which is a more traditional looking faction symbol with a white border (to distinguish the purple symbol from the purple mixing drum).
EDIT: Overload has a symbol like that too.
Overall this set looks cheap and horrid. Which is a shame because in terms of the figures themselves I think they're really really nice and definitely worth a buy. Just not this. Get the normal release over this, or indeed get the Japanese version of the G1 homage set.