I think the reason I break fewer arrows with Judos is that I get fewer of the glancing shots which seem to be the nemesis of all wooden arrows. Having said that I ought to point out that I buy cedar shafts selectively--only raw shafts weighing at least 370 grains and 390-410 is better. I do it for the weight, but I presume denser wood tends to be tougher. I haven't found sitka or fir to be appreciably tougher than cedar. For my $ when it comes to hardwood shafts there's nothing that even comes close to Bill Bonczar's laminated birches.