Which Hoover WT cleans carpets better:  original, WT2 or Savvy?  I tried all 3 & to me I think they clean the same but I prefer the Savvy & WT2 b/c of lifetime belt; but the WT & WT2 have spiral agitator.  Does the spiral shaped agitator REALLY enhance deep cleaning?  I wish they had metal brush rolls & METAL beater bars (like the older Hoovers) instead of cheap plastic rollers.  I really don't know which one to buy & add to my collection of vacs, but I prefer bags or bag/bagless (Savvy 2-1); but I wish the Savvy had 2 wands instead of 1 or a metal telescope wand.
 
How good is the WT Bagless Canister?  I didn't like that it doesn't have a good duster brush & the PN doesn't have overload protection.

The Hoover "activator" (auger agitator, such as fitted to the USA "Conquest" heavy-duty uprights apparently can out-clean the quadraflex agitator as fitted to most American Hoover uprights).