Dimension...
Is this the plastic, Dimension (Elite) uprght? Or the Dimension 1000 Canister? I'm assuming it's the Dimension upright...
It's hard to compare the machines. In my opinion--if the Kirby had a new brushroll, belt, and spotless bag on it, they would probably clean comparably to one another. Those little Hoovers were quite the workhorses, and did a great job. Kirbys, however, (especially the older ones)don't tend to "vibrate" the carpet, and get the sand to the surface. Thus leaving the carpet dirty. THe Hoover also has firm bristles on its agitator--thats why its grooming your carpet nicely.
The one advantage the Kirby has over the Hoover is center suction.