For the last few years I've been skeptical about the cleaning capabilities of these type of robots. I decided to get the Roomba i3 based on the performance of the series 6 at a friend's house. After receiving my item and opening the box, it was a simple installation and was up and running in no time. I let it charge for a few hours before its first run. That evening I let it clean the common area in my house, I was amazed how much it cleaned everywhere, I had to raise my sofas one inch in order for the Roomba to clean underneath, it was worth it. Now I set the schedule to clean at 2 AM every day, even that the manufacturer recommends light for the robot to clean, this i3 preforms superb in minimal to no illumination. I definitely recommend the i3. It cleans, covers the entire floor, recharges when job is not complete, and it recognizes object and slowly bumps into them. The only thing missing is the capability to recognize rooms and avoid designated areas; these features are available at a higher price on the i7.