I have no experience to share, but I will mention what the shop manager where I bought my bike told me. He races XC and he said if he's doing short races he always rides a hardtail, but if he's doing longer and/or endurance races he always rides a FS. He said it's just too hard on his body on the long rides. He's 25 and in excellent shape for what it's worth.
Good luck on your search and let us know how it turns out for you.