This thing was a booger to put together even with the instructions. It's quiet but I have to refill it every other day, not really a problem, but you have to stay on top of it so the motor doesn't burn up.  Small filter fits securely into its slot, doesn't take up much room, less than their previous water bowl, & I know that they're getting good quality water. The cats were afraid of it until I dragged the older cat over to it.  She started to drink while the younger cat looked at her in awe, she's brave!  It was 12 hours before the younger cat became thirsty enough to give it a try.