Razorcaps are higher quality, stronger and like Buff said hold an edge better too. A little harder to sharpen than the Woodsmans because of the harder steel.
Woodsmans should have a slight penetration edge, although I can't tell the difference, and all the advantages of the Razorcap you definitely pay for. They won't kill any better, just do it with a little more style.
All that is IMO of course, and based on experience regarding the original 'Caps. I have no knowledge of the NAP version.
Really a win-win. :D