Of the few animes I've watched, this one is an instant personal favourite of mine. Character development and a strong theme on it's plot. While the buildup is slow in the first episodes, it begins to slowly pull your heartstrings with flashbacks and emotional scenes.
The last few episodes are were it's at. As it begins to bring in the onions and make you want to cry. Top it all off with quite a tear jerking ending an this show will leave you shedding; if not sobbing fat tears down your face.
Overall, I recommend this for those who like animes like Your Lie In April or Angel Beats. Since it's not for everyone.
Overall, this is one of, if not the most tear jerking anime if the decade.