the advantages are in the stiffness to weight ratios and the overall strength of the boards.

still nothing wrong with building an all glass board, especially with a wave board but for slalom and speed sailing the stiffer the board the better because it will be faster. one advantage with a pure glass board is that if you break it it can be fixed easily. boards that aren't as stiff feel better in chop and surf because they flex a little and absorb the tendency to bounce.

however
advances in rocker line have meant that really stiff boards now handle chop very well. where as with old school designs the stiff boards used to bounce around.

the only real difference as far as materials go is the introduction of plywood into the layup. having a stronger layup means less creased boards if you are pushing the limits with jumps. now the boards tend to just break but take a lot more punishment before they do. my race and slalom boards have been using carbon/kevlar for at least 15 years.

so carbon is used to get the stiffness and a plywood laminate, which is as cheap as chips, gives the impact strength. plywood is even better than glass for that.

vacuum bagging has meant that the weight can be kept to a minimum as well due to less resin being required.

So i think that the advantages are real in terms of performance and strength. wide boards especially demand the modern construction techniques to stop them falling apart.

i used to hate sailing the older type plastic boards like the mistrals etc for race/slalom because i found they would flex to much for my liking. i preferred custom stuff because it offered way more stiffness.

these days most major board manufacturers are using stiffer layups. so there is now no real difference. to the point where a pro will use a producton board to compete at the highest level.

i still prefer my customs though, because they are shaped to suit me and i can get them repaired by the builder. it is a shame that most of the aussie board builders are dissapearing. either can't compete with the big boys pricing structure or have become alergic to the resins.