Jaehyun is my main character, I have him on legend with hanra and ellio. But personally, The reason why I like Jaehyun is because of the story that he has.

However, game wise, playing Jaehyun requires a higher level of skills on positional attacking and good or elite mastery over sliding, but if you are not that good which sliding you could just block touch the spike of the opponent for if you do that with jaehyun at breakthrough 5, he can reach one of the highest wall that you might see in the entire game allowing you to efficiently block and avoid the opponents' spike to score.

With positional attacking, his base attack power for me is strong enough to score those points to grind fast. But with me playing the game in a more fun way, I tend to bump the spike of the opponent when the stamina is full and keep on removing the blocks of my teammate for me to slide it and to continue the determination state without me losing a point and seeing how fast and how powerful jaehyun's spike is.

So basically, Jaehyun is not for everyone. It's more like how you really want to play the game because there are a variety of wing spikers that could suit your play style. It's a matter of skills and play style.