I have one...and at least one of my cats can't get enough of the dang things. Why's that, you ask? Because it was given to us for free. Had we paid any money for it, I guarantee that none of the cats would touch it. Because it was free, they're all over it.

As for it getting gunked up, I just hit it with the vacuum if I happen to be cleaning. Looks brand new.

I'm going to guess that Paris Hilton desperately wants to add little Kenadie to her minipet menagerie.