The 570 is pretty close in performance to the 580 and has higher air speed, which should scour stuck debris better. No hip belt though.
I was a little disappointed with the scouring ability of the 580 for such a big and powerful blower. I'm a tall guy and to scour I have to point it right in front of my feet, which results in some "backwash" going behind me. I bought an extra intermediate tube for it for when I'm scouring a lot of stuck stuff and for blasting out drainage ditches and stuff. I'm used to longer tubes like on the Shindaiwa machines and would rather be working out in front of myself more than at my feet. I had the same problem when I demo'd the Echo 770 though which also has short tubes.