Leopold, Beandip, Pumpkin, and Pixel are pretty much just indifferent about it. They don't get real close, but they're OK with watching me from 10+ feet away.
Pixel used to be completely fearless about it, but I had to purposely dangle the nozzle at her one day, because I was on a ladder with it running and she was working on knocking us both off the ladder.
I couldn't reach the switch so that was my only option.
Junior,Precious, and Momma are scared of it.
Paisley has no respect for the vacuum monster...I have to be careful to not run right over her with it. She thinks it's fun to play "chicken" with it.