I thought I would need the tooth bar as I planned on digging and grading with the loader. I passed on it because of the price.
Now I don't think I need one. I have been amazed at how well I can dig and grade with the cutting edge even into some rather hard virgin soil. I tilt the bucket down and raise the tractor with it. Then a little forward motion with the weight of the tractor on the blade and a curl up with the bucket and it digs everything I have asked of it so far. I thought I would be using the box blade more for grading. However the FEL has been more useful so far for the heavy stuff.. However I wouldn't give up either as they are both very useful. I just don't know what I would use the tooth bar for and I wouldn't want to give up the smooth surface that the cutting edge leaves.
Zeuspaul