860 and 880 are using exactly same cleaning system, which means they have the same cleaning performance. The only difference is that 880 has 2 Lighthouse and remote control. Actually 860 has longer battery life than 880 75min Vs 60mins. I did lots of homework before purchasing roomba, and finally brought 860. I have two cats, and I am very pleased with my choice so far ! See the link below for more info is you want to ~~http://dadvocated.com/Roomba-860-Vs-880/