Most of the differences between Battle Frontier and Battle Galaxy seem to be in the upper body, with Battle Galaxy having a different head, forward flight deck(arms), shoulders and those fins at the back.
In any case, both look way more menacing than Battle 7 - what with it's blue on white colour scheme (Max's colours?) and big red M on it's torso (makes it look like an old school super robot). Off course, the fact that individually, both have more guns than Battle 7 does help.