Well, on medium duty; I define it as heavier/better built than the typical light duty; but still below heavy duty or commercial. Honestly, all of the equipment makers also really like to throw the name "heavy duty" around, even for the lowest of the low end.
Also, even the expensive, big names, make some models that are pretty light duty.
So, im thinking the BH215, I think is the model, is what im calling "medium", and a BH 115 would be light duty. So, maybe a better way of asking, what are other models in a similar "weight class" from other makers, like Woods, Landpride, JBar, ect.