I replaced my Nautor mast 4 years ago with a carbon mast made by Axxon. We have been doing a fair bit of racing since and we have noticed an improvement in performance, difficult to identify exactly why as we have made some other changes too, incl racing carbon sails etc. So far so good, the mast is in great condition, there have been no issues, but we exercise much more care with halyards etc, as it is painted awlgrip white. As we also changed some of the rigging to PBO, we have lightened the whole rig which created some fore and aft trim issues which we have dealt with by moving stuff around inside the boat - notably the genset!
I would do it again, I am not sure of the life of the PBO rigging, probably less than rod, and it does require great care as it is vulnerable to chafe. Our V1's are rod because of overlapping genoas, but our forward lowers are taking some heavy chafing, I should of had those in SS Rod too I think.
Axxon have developed a good name for themselves amongst the french offshore racing scene, and were very favorably priced when I got mine, they are more established now I think.
If you are interested in exposing the more athletic side of your boat, its a good way to go I reckon.