I did a fair amount of research on this a couple of months ago, because I really wanted one for myself (three cats, nuff said), and found that a lot of people were having to take theirs back several times to get a 'good one' that worked, and that the self-charging mechanism some of the newer ones have often don't work reliably. I decided based on what I saw to wait another year and see what came out and whether the new ones would turn out to have better longevityand reliability than the older ones. Plus, other makers are starting to make competing models, which might bring the price down.

If you get one, please tell us how it works out, though. They're the coolest things IMHO, if they work well.