I'll do a review on the BR 600 when I get to use the thing for a while and I can compare it to the BR 380 and 550 as far as the KM 56 you mention, I don't have ant Kombi units. I don't like the idea of those for commercial work. They would be good for the home owner or home use where time isn't a factor but for me that would be worse than replacing string on a trimmer head when your out in the field which I don't do. I think what you saw or seen was the HL 45 Hedge trimmer on the bed of the trailer.