I know it's an old thread, but I just bought a new (2021) 590M. Really like it, but dang, those revs are so high, and even when I'm asking for so little.
So if someone has any new info, I'm interested.
Overall, love it. It's great for little tasks around the homestead. But when heading down the road to the neighbors, the high revs and the associated noise and vibration seem to be more than needed, especially on flat stretches or even slight down hill running where I could just about maintain speed by popping it into neutral and coasting (not gonna do that, but just sayin').