Loved mine, but it only lasted 2 months. :cry:

I had a second generation model (better battery, larger dust bin). There were optical sensors that got dirty too easily, and if you don't know where they are and how to get to them to clean them, Roomba started going in a "circle of death" or just stop, start, stop, start, and move erratically until it error'ed out.

I hope the problem has been fixed by now.