"My hamster loves his ball. He runs all over the place in it. I use it on my hardwood floor so it rolls really well. However, I've also used it on carpet and it worked well there, too. My cat is a "rodent-hunter" and even he doesn't go anywhere near my hamster when he's in his ball. If anything, he avoids him because the hamster chases the cat. The only problems I have with this product are...
(1) It leaks. When the hamster relieves himself, it goes right through the cracks. It makes a total mess. It's worth it, though. Just expect to be doing a lot of clean-up.
(2) After a while, the lock stops working. My hamster escaped so I don't use it anymore. I suspect I just need a new one. I've had it for a while (this is the third hamster to use it). Just be aware of the possibility of escape once the ball gets old.
Even with the problems I have, I still recommend this product. It's the only way I know of to get my hamster really good exercise (besides his wheel). And it helps to curb his curiosity. He can explore new places and chase the cat while he's at it."