We've owned 2 of the 900 Series Roomba. My main dislike was that it filled quickly with our 4 dogs' hairs. I'd find the units dead underneath beds or furniture. Now to recharge it would take hours. So, cleaning would be incomplete. Upon picking up each unit, to bring it back to the charge station, It'd fall right out of my hands because I'd unknowingly grab it from the pull out trash tray! Twice same accident. First time they kindly replaced my unit. I was so proud of my purchase. But the second time, within 3 months, too bad-so sad! $900 down the drain! So, thought this unit would be my solution. After reading these reviews, sounds like this one needs a lot of improvements before I'd pay this much money for a vacuum.