As a kid we had a lot of fun watching our hamsters run around in these things. There are two problems however. If you have small pets and a baby don't let the two in the same room with the pet in here. While I have never personally had the problem, I can certainly see my son picking the ball up or accidently kicking it while he is chasing it all over the house. The other one that I did have experience with is cleaning this. When they go to the bathroom in here, the small opening for them does not always accomodate the cleaning equipment and hand as nicely as it could if it were just a bit bigger.

Pros: Exercise and Amusement!

Cons: Babies and Cleaning it out!

When we had hamsters, they loved running all over the house and it keeps them safe.

Pros: fun

Cons: none

My hamster enjoys running about in this for some exercise.

Pros: Sturdy

Cons: none.

These are really good for hamsters, gerbils, and mice but way too small for guinea pigs, ferret, chinchillas, and rats (yes people have asked me if this was safe for these guys).

Pros: It's a great way to protect your pet while it's out of the cage

Cons: Just watch them around stairs and overactive children

These are the best. We have used them for gerbils and hamsters. They all are so much fun to watch take off in these

Pros: fun to watch, great exercise for gerbils

Cons: hard to clean