I got one for my guys this past Christmas and they love it. Unfortunately it gets dirtly quickly and the pump get clogged with hair frequently. They should have designed it with the filter before the pump, not after.

If you ever have problems with the pump slowing down or stopping you can usually clean it and get it going again. Here's a website that shows you how to do it.
http://www.felinediabetes.com/petmat...w_cleaning.htm

Hope your kitties enjoy it. It took a couple of days for all of mine to get the hang of it.