The best set of Roomba models on the market as of 2015 is the Roomba 800 series. The Roomba 880, the most recent update to this series, is the most feature-rich Roomba model available.
Roomba is the world's leading brand of robotic vacuum cleaners. The units in the 800 series have a number of features that put them above previous model iterations. These features include the AeroForce cleaning system, HEPA filters, room-to-room navigation and an expanded iRobot XLife battery pack. The best Roomba product in terms of value for the money is the Roomba 650, but this older model has fewer features.