I've ridden every Norba course in TX, a few in LA & AR without issue, FS doesn't doo too much to benefit a decent rider on technical singletrack courses, the only place I thought it'd be fun to have one was the course at la jitas out near the davis mountains in west Texas, where they have the cactus cup, but even there a hardtail was fine.
If you go from an x-mart FS to, say, an entry to mid-level hardtail, you will notice a significant increase in performance, a tremedous weight difference, smooth shifting, your enjoyment mountain biking will be x100