S.G.
We've got a Kirby and a Roomba (regular red one) and a Scooba. The one thing I have to worry about with the Roomba (or any vacuum for that matter) is that I have to "pre-flight check" the floor for small toys and string, etc. before I vacuum; you get a lot of tears if you vacuum up the Barbie shoes by accident. With the Discovery model, I'm afraid that I might not get that "pre-check" done before it takes off.
Still, it forces me to tidy up once in a while and get the girls' clothes and toys off the floor. We've got three cats, one of which is VERY long-haired, and the Roomba is full of cat hair DAILY now. Since it goes under couches and beds (but a regular vacuum doesn't) it picks up lots of hair from the favorite hiding places.