Personal opinion as I have no technical data to back this up but.....I do feel safer using ACC's or my A/C Superslims. Why? Because in the event I do not find a crack, split, etc. initially, if their is one in the carbon outer shell, I feel safer shooting them. On another note: though they(ACCs and A/C Superslims) are expensive, so are some of the top end carbons manufactured these days. I have also found that my A/C Superslims are much tougher than some give aluminum/carbon arrows credit for. I have made a shot or two with mine[:-] that would have shattered most any carbons....and they remained as straight as they were when I bought them.

Again, just in case I don't find a hairline crack if there is one, I do feel safer shooting the aluminum/carbon. Just my opinion.