I have run both carbs on my 360,and like them both.
I think you will be suprised with the 600. Very snappy carb, all in all works well.
The only difference I can tell between the two, is the top end.
The 750 takes over once you get into the upper RPM's.
Not by much, but it does.
Curently I am running the 750, but would have no problem switching back to the 600.