Instruct: Classify the given review as either positive or negative.
Query: Wonderful Automatic Litter Box!!!

I really love this litter box. I purchased the hood with it and have had it set up for 2 weeks. With two cats, there is absolutely no odor! My adult cats took very quickly to the new box. For the first few days I would sprinkle some of their regular litter to help them learn. I left the old box up until they were comfortable with this new one.There are a few drawbacks (that's why it's a 4):Size-this is very large, I had to place in the bathroom for plug in. But with the lid on, it's not not offending and once again, no smell!Noise-it is a bit loud when cycling. The first few nights it woke me up (bathroom not far from bedroom) but now I don't notice it anymore.Price-the refills are expensive, so I just ordered a Forever litter pan from e-bay. Now I can get the crystals from the store and it's good to go.I'm most impressed by the lack of smell! I've never used crystals before and now I can't imagine using anything else. Overall I'm very happy with this purchase.