I have heard of these, but not tried them. I went through a couple of different ones before finding our current beds, which are desctructable in my house!!
We tried the pillow ones, and the foam filled ones--both were destroyed
Then I found ours at Target one day: $24, made by Woolrich--the BEST!!!! They all love them, don't destroy them, and they clean wonderfully!!!!

Here's a link:
http://www.target.com/gp/detail.html...sin=B00008W7HP