I picked up the basic Freud SD206 6" stacked dado set on sale at a local hardware store.  Despite what some reviewers have written here, I had no problem mouting this dado stack on my DeWalt 746 table saw.  Granted, when all of the chippers are in use the arbor is completely filled - but it does fit.  After making many 1/2" deep and 3/4" wide cuts in white oak I found the performance of this dado stack to be excellent.  There was no chipping or tearout whatsoever when I was cutting with the grain and only very minor chipping when cutting across the grain.  The dado cuts were very smooth on all surfaces and the bottom of the cut was perfectly flat.  Also, I was happy to see that the shims included were of very high quality (thin metal rather than paper).