Well viewing the anime from my own perpective, I've always had a little intrest in volleyball since I was thirteen but never took the initiative to do somehting about it, but after watching the show, I really feel that I want to start training volleyball even if I'm a little older now, but it's better to late than never. It gives yo the kind of courage and motivates you, that's just what happened to me, however as I stated before, I was already intrested in volleyball so this might not apply to everyone.
The art is nice and the animation has good quality, yet to be honest at first I wasn't so used to the character design itself because it's quite different in a way compared to others that I've seen, but I got used to it after watching some episodes so it's no big deal.. However, the sound isn't really something so special, and the songs aren't the best but it doesn't really effect the anime at all, but it would be nice sometimes to sing/hum good anime songs to get some flashbacks on them and get intrested in watching some major moments from the anime just randomly on youtube or somthing similiar.
The final thing I want to state are the characters. Every character has their own speacilty and are all included equally in the story even though there are main characters. You maybe won't fully see it in the first season but there's also a second season that continues to show that with the other characters. And obviously, in all animes, the characters are always one of the most important things in making an anime sucessfull.
