I don't know about the best but defiantly of my all time favorites, it made me cry more than once that's for sure and it still gives me feels lol though I suppose that's par for the course on KEY anime I mean Clannad After Story had me weaping like a baby (AS actually is my favorite anime ever lol)
Angel Beats is amazingly impressive for 13 episodes, but I do wish there were more of them so we could get some development for other characters. I also kinda wish the ending went into more detail so that we see what the next lives of the others are like, such as Yuri, Yui and Hinata, and a bit more detail with Kanade and Otonashi and what they live like. Does Otonashi have a sister again for example? Well, at least the main 2 are reunited.
The ending of Angel Beats was one of the most beautiful things I have ever seen. The revelation of Yuzuru and Kanade connection took me completely by surprise. I did not see that coming and I started tearing up. I have seen many stories were characters give their hearts to one another but Yuzura Literally gave Kanade his heart. I’m glad they find each other again. Yuzuru and Kanade may not realize it but they are in ever since of the word, True Angels. Maybe that’s why god decides to reincarnate them. Their reincarnation is in a way both their reward and a duty. While everyone else passed on he sent them back for the world needs people like them, people who will help others without a second thought. The best thing is that they can now help people together just like they helped the battlefront and at the same time have the opportunity to fall in love all over again. Yuzuru and Kanade may have not been Angels when the series began but in the end, the way I interpret it, Angels are exactly what they became.