I have two dogs who shed.  A lot.  We run our Bob every other day and the amount of dog hair all over the floor has decreased dramatically.  Sometimes Bob appears to be a little confused and it seems like he is never going to make it to the other side of the room, however, if you just let him go, he gets all of the spots he is supposed to.  
We sweep out the corners and under the couch because he cannot always get to them, but he still does an amazing job.  He has only gotten caught up a few times, but if we are sitting on the couch, it is usually easy enough to pull the remote control out and redirect him.  
I loved the way he arrived, complete with a birth announcement.  He really is a part of our family, now that the dogs have finally gotten used to the weird round thing that makes noise and moves all by itself.