I've had Bissell vacuums all my life and then more expensive Shark models. When I upgraded my Shark vacuum 3 years ago I was blown away. The biggest annoyance is the spread of dirt, hair, debris, etc. on hard floors. Also, the Sharks' traction hindered more than it helped, kicking and struggling, and barely clearing with any backward movement. It also didn't reliably pick up things along walls, edges, trim, etc. Leave hair on steps, corners and carpets. All in all, it was a significant amount…