The Aputure 600D has a 720 watt draw, the Forza 720B has 773 watts and Forza 720 (daylight) has a 750 watt draw. I think the most important difference is the Forza 720's have a larger COB chip meaning the output should be more even with less falloff.
Amazing light!!! I got the fs-300 and working with some rosco filters, I can change colour and Kelvin temperature ... hope some day try a baby like this Forza 720b. Thanks for the review