The Dwin gives a slightly brighter image, the NEC has color filtered lenses for much better colors. The Dwin is completely silent with no fans, it weighs 65 lbs., and has a rather small footprint. The NEC has roughly (45 decibels) worth of fans, weighs ~125lbs., and is larger in size to the NEC. The Dwin is very user friendly to setup, the NEC has more fine tuning adjustments but is a little harder to setup.
Both are great projectors. I own a NEC 6PG and it's one of the best 7" CRT projectors around. I would take the NEC over the Dwin only because I really, really enjoy the colors from the NEC CRT projectors. Reds look Red (not orange-ish), and Greens look Green (not yellow-ish).