I've always enjoyed this type of HB when I've used them-they have a cool look all their own. I also have one labeled "Philips" from Canada I got from Pete. One of my favorites is the Model H, where you have the styling like the unit on the right, but still the speed control in the window rather than printed down the side. It's best to have the original equipment beaters I find, as the aftermarket ones have posts in the center of the beaters themselves, and I like it better when they don't.
I did notice progressively higher wattages on the mixers as time went on, from 120 to 150 to 175 etc, but that doesn't of course necessarily mean anything. I find these older mixers stronger than some newer ones with several times higher wattage motors.
HB also had two other lines of mixers in the 70s, that with the really square stand and motor, with separate beaters but the same style bowl, and another where the motor unit is very round with the speed control on front, and the stand kind of square. I seem to recall that had Sunbeamish beaters and a slightly different bowl. I remember seeing a lot of rebadged Sears ones like that, which made me wonder if the ones like your green one were a predecessor to that. Not sure how they all were marketed, if they were sold in different types of retailers or whatever the case.