I bought a Roomba 850 about a year ago on here and it is a vast improvement over the Roomba 680. This model has an icon that tells me when the bin is full, and just in case I don’t get the hint, it refuses to do it’s scheduled clean until the bin is emptied. Roomba 850 also is able to find home. My 680 had problems with that after the first year of service. It appears that the only difference between the 850 and 860 is battery size.