I agree, I think they are better for younger kids (3-5 year olds). I have a 3 year old son and a 5 year old daughter and they love them. We get them for all their friends/cousin's birthday because they love them so much. The kids that we have given them too also love them. I think that you have to keep adding to the "house" to keep it interesting (luckly they are in expensive for the accessories and such). My kids get to earn money to buy accessories.
Also, they are good for kids who want a pet. They can "take care" of them. If they get bored after a couple weeks you can explain that is what happens with a real pet but you can't just toss a cat in the toy box.
The hair thing that someone brought up, its true. There is a warning on the pet itself about it. my daughter has hair passed her bottom and she got it tangled...we just cut it out and reminded her to not to lay down on the floor while playing (unless her hair was pulled back), same with any moving toy...
As for the batteries, I would say that my kids play with them as often as any other toy and we have had theirs almost a year and we have only changed the batteries once.
GOOD LUCK!