iRobot Roomba i3 vs iRobot Roomba i4

The iRobot Roomba i4 is a better robot vacuum than the iRobot Roomba i3. The i4 has a better cleaning performance on low and high-pile carpet. Since it doesn't have an external dirtbag, it has fewer recurring costs. Also, it comes with a Dual Virtual Barrier Device, which lets you mark areas for the vacuum to avoid while cleaning. That said, the i3 does a better job of cleaning bare floors, and it has a larger dirt compartment. Also, it comes with an external dustbin attached to the docking station, so it can automatically empty its dirt compartment.