At first it worked ok.  It does seem to back track as lot.  It had trouble going into different rooms.  The settings are not user friendly.  You have to choose a certain setting in order to enable it to vacuum a patterned rug.  After a while no matter which setting I put it on the thing would not vacuum the printed rug.  It reads the color changes as steps or walls, apparently.   Now the thing won't work at all, even on a hard floor.  It travels about 6 inches then stops.