It depends on the type of filler really, some of them are great comic relief and good for a laugh. Others are more serious and show a good back story of a character or characters, such as said above the Kakashi Anbu arc. From 441 its getting good, its nice to see a different turn of events such as Minato still being alive and having the 3rd as his advisor. Having the Uchihas still alive showing that Sasuke would have gone bad regardless of what kind of childhood he had. All these kind of fillers a good to watch but there are stupid ones as well.