The was a thread on it, do a search. Someone said the WM has an aluminum tub, whereas the NP has a plywood joiner for the wing. Retract issues appear as well. The wm had issues early production, but later improved. I can't find anyone who has built the np version. I was looking at it myself. May order one tomorrow. $169.00 Jeez...great price. The wm was $389.00 in the beginning. They look like the same bird, infact the np is better looking...IMHO