In my experience you will score a bit more often on hardwoods but the harder woods finish cleaner. I have more trouble with larger growth rings than I do with harder woods, with the exception of white oak which is tough with any but the sharpest of axes due to the tangential fibers. We did a project with fast grown yellow pine that worked us over, the axes would drag in the softer layers and tend to gouge unless you changed your angle of attack. Walnut is one of the easiest woods to hew.
