I bought my first littermaid about 4 years ago, have never regretted it.  It's much better than having to change a cat box and I don't have the cat box smell.  It is a little work to change the receptacles sometimes if they get too full, but I just dump the whole thing in a plastic grocery bag and take it out to th e trash.  I would recommend keeping your receipt and box in case you have problems.  They have a 1 year guarantee on them and I had to send mine back once because it quit working and they sent me a new one no problem.