Dave; I own a HS520AS snow. The single stage unit works VERY well. I think the thrower weighs in at 80 pounds. Much lighter than my old 280 pound Ariens 8hp 2 stage unit.
I can throw just about ANY snow between 15 - 30 feet. Naturally the lighter and less slushy the farther. I have never clogged the chute on the unit at all. As far as two stage unit, HA! You take some nice slush and watch a big powerful unit barely throw the snow a few feet away. The single stage unit are self propelled. Not the same as a two stage unit that has a transmission, but basically you tilt the unit forward a bit and the rubber auger starts marching the machine forward.
The other poster saying that the two stage unit breaks up the driveway mess the town leaves is absolutely true. The single stage unit doesnt like to break up ice. The metal auger on the two stage units works great on that one.
I been on both sides of the single vs two stage debate.For the physical size, location and my size driveway I got the perfect machine. I live in Long Island, NY Not too many storms around here like Albany, but we can have some severe ones.
Honda power equipment has some really nice stuff. I have no doubt that this unit will last me a number of years. I like the simplicity of the single stage units. You basically have an engine, belt and auger. No transmissions, no differential.
If you want to save some money dont get the AS (that one has electric start) get the standard one without it. With the honda stuff you really only need one or two pulls to get it going.