I do have two Neilpryde carbon booms (matrix 2000, 200-248 and 220-268); the're about 7 years in use and stil ok. 7 years for a Nautix alu boom is very good.
@JeanMarc: That test in the German Surf Magazine also showed that a carbon end in a aluminium boom doesn't make the boom stiffer, but it's much more expensive.
check the difference between the NP X3 and X6:
NP X3 € 230/ 27 / 22
NP X6 hybrid € 449/ 28 / 23