I'm having pretty good luck with it, though I find I need to check the bow and shaft specs very carefully. Bought a scale and found bows weren't quite what I thought they were, was mistaken about the center cut on a couple, too. I think when I put the right information in, I get a good arrow, though maybe a little stiff. The new version has quite a few bows and shafts listed, so that should help. Even if a particular bow isn't listed, there seems to be something close for comparison. I've found enough variance spine testing carbon arrows to account for an extra inch needed to work properly. A few small differences could add up and account for an extra inch of arrow pretty easily. I'm glad to hear it's not suggesting you cut the arrows too short!