TL;DR - Beautiful music and animation with meh characters.
I mostly like the show. The music is incredible, and they did a really great job with the animation. Even if it's not 100% accurate with finger movements, there's a lot of detail and finesse that's mostly skipped over in other music-themed shows. You actually see all the subtle picking and strumming animations, and the finger movements are also done very well. So in terms of aesthetics, definitely amazing.
Even the overall story is interesting and fairly good. It's got a fine premise, and I like competitions as well as underdog stories, which we get.
What I dislike, however, are some of the important characters. Everything about the main character, for example, including how he's sometimes an ass, is half-assed.
We're given the premise that he's a genius musician guy who's "lost" and struggling to find his sound because of his grandfather's death, yatta yatta yatta. But his behavior is too stoic for that. He seems like he's unaffected and uninterested in most things, but when it counts, he's suddenly this passionate, gung-ho guy who suddenly pays attention to and cares about everyone. They justify this totally BS bipolar behavior with his "quirk" that his skill level is entirely determined by how he's feeling when he performs. Which could be interesting! But it's poorly executed.
I equally dislike a lot of the side characters. It really doesn't spend the required time building up side characters and their motivations. The premise for each of them joining the Shamisen Appreciation Club is nonsensical, and there are dramatic moments that come across as melodramatic because again, we didn't really get enough time to care about or understand them.
Shuri has done nothing all show except being shy, crying, and getting upset (mostly at herself for being useless), which is ironically what makes her a useless character. Otaku girl Yui makes zero sense. Why is she doing any of this? Kaito is supposed to be the straightforward, energetic, and passionate guy who acts as a foil to our MC, but the only thing he's done all show is getting mad at MC for being stoic. Rai is semi-interesting, but again, we don't explore character backgrounds, so he just shows up as the friendly, funny, gay guy who happens to already have musical skills.
From what I've seen so far, every other character and their background are just plot devices for our MC to "find his sound."
Another thing that really pissed me off is the first episode. The description of the show/manga makes Yuna, the first girl you meet, to be this super important character who helped him find his sound again. But then after the first episode, she disappears to "go find her dream" and then our MC is back to being lost again. What the hell was the first episode even for? Why aren't we getting more Yuna, who was actually a likable character?