What shape is the North, new or old school? I had the new school version with the square-ish front bend and found it was way better as it doesn't knacker your arms out as much. However I found the clamp was horrendous for snapping when closing on the beach, the grey section splits where the rope goes around the boom, so after two going I've gone for the new Neil Pryde X6.
IMO the NPs are very stiff, carbon back end, but still light and comfortable in the hands with the added narrow diameter for long sessions and easy grip.
A friend also likes his new Amex carbon boom with a slight V grip and says its really comfortable for long wave sessions out of the harness....although the clamp snapped on him at K-Bay after two months of use (which they have replaced under warranty of course)