I'd give the same comments as pvrp.
I've got a couple of Ariens machines here with them and a SnowKing (Murray) 12hp with teeth even more pronounced than on Ariens machine. They are not so helpful but seem to gain a few inches in hardpack over machines without them. They might be more helpful in crunching hardpack that has been gathered for better flow out than digging into piles of hardpack.
Today I used an Ariens 11.5 24 inch 924 modern tall chute machine into sidewalk buildup which it went through but struggled and lifted on. The pile was old sidewalk buildup plus new buildup. A lot of snow went under the bucket. I left some of the pile and went back with an old Jacobson Heavy Duty 5hp 26inch went through the pile better. It had much smaller wheels but did have chains. It stayed lower and cleaned better. The first speed on the 11.5 was too fast but I can possibly adjust that lower. WIth the Jacobson I did have to ride the clutch to slow it down also but it's a 5 and went through without a difficult struggle. The Jacobson has a heavier bucket than the Ariens, no teeth on the auger and lower RPM auger.
David http://www.kedawei.com/snowblower.htm