Fiber has lower latency and jitter with all things being equal. But I doubt you'll be able to detect much of a difference in jitter (who knows what the ISP does to the signal before it hits the fiber network leg). Latency is much more likely to be better. I know it made a big difference in my situation. Even things like Netflix loaded much quicker (I had 1G copper and switched to 1G fiber). And it led me to eventually switching my LAN from copper to single mode fiber. I stream a crap ton of stuff off my media NAS as well my music NAS - both located in my LAN. With copper, it took several seconds to que up a 4K movie. With fiber, it's less than half and probably closer to 1/4 the time. I had a 50' run of copper from router to media area. That makes a difference as well.
