I have to admit that I had a 100% carbon Gulftech 490 SDM (originally made at their Texas facility) in the late 90s that ultimately failed due to cam wear. It broke above the boom on the outside at Coyote Point, but I was able to sail back on the remaining 2/3rd left with a folded over section banging on the boom. Admittedly, I was quite lucky to be able to sail it in.
Despite my misfortune, it was an absolutely awesome mast until it died. In fact, I still have the unbroken section, to include the 7.7 sail that was damaged by the break in the mast.
Although there appears to be some dissatisfaction with high carbon content masts, I have to say that all mine have been great. Not all of them have lasted forever, but I always got at least 3-4 years before failure. Even though I'm a bit of a lightweight (70 kgs), I must admit that I have been able to leverage well off these masts.
Overall, I had to say that my experience with 100% carbon masts has been very positive. However, I have to be frank that I wouldn't invest in a 100% carbon NP mast. No reason to gamble on a historically questionable product. I think 2006 was undoubtedly a black year for NP. It's hard to recover from such a poor show.