I have 2 8500's. Way more power than the 8050's. Uses more fuel and is louder. Lighter. Taller and narrower so is a bit top heavy, if you keep them in the back of your truck. The back pad is a little different but no less comfortable. I like the handle on the air tube in that the handle rotates rather than the tube itself. Seems like a nice feature.
Paid $540 total for one and $568(paid extra $25 for shipping/special order) for the other.
One other thing, being a strato-charged engine they are a bit harder to start when cold. If warm, they start first or second pull.