iRobot Roomba i7 vs iRobot Roomba i4

The iRobot Roomba i7 is a better vacuum than the iRobot Roomba i4. The i7 does a much better job of clearing pet hair from all surface types, and it has a larger dirt compartment. Also, it uses the iAdapt 3.0 with Visual Navigation system to follow an efficient route, and it learns its environment as it cleans. There's an external dustbin attached to the docking station, so it can automatically empty its dirt compartment. That said, the i4 doesn't have an external dirtbag, which results in fewer recurring costs, and it has a longer battery life.