Easily one of the funniest and sweetest highschool manga I've read. As a fan of delinquent manga, it was especially enjoyable to read a 'reverse delinquent' manga, as it were, seeing as the entire premise is that the main character's natural appearance makes him look like the worst delinquent spawn of satan villain to exist on God's earth, while his true character is that of an angel - hence the title. It's quite similar to Waratte! Sotomura-san in this single sense, in that everything the protagonist does is misread and reinforces their delinquent image despite the intentions. Unlike Waratte! Sotomura-san, which is a 4-koma gag manga on this premise, Angel Densetsu is a full monthly-issue-chapter-size slice of life manga.
This manga has come under a little criticism for the quality of its art, and I can kinda see where they're coming from if they were only talking about the first chapter or the first volume. But the art markedly improves over the course of the manga, to the point that it is clearly recognizable as the same mangaka who created Claymore (for it is he) by the latter stages, I would argue even as early as vol. 5.
Beside that, most people can get over bad art for a good story (case in point - the people that read ONE's original webcomic of Onepunch-Man), and this is a pretty good story. The repetition of "different people see Kitano's face, overreact at his terrifying visage and do stupid things" could get old quickly for some people, but it's a joke that is spun differently with every new person so that it keeps fresh, and soon enough, an assembly of different characters each funny in their own way come together around him and comedy, friendship, characters and relationships develop as naturally as if it was always meant to be like that.
To quote/paraphrase the author - "I'd prefer if people didn't read this as a manga called Angel Densetsu that some guy drew, but as peering into the world of Hekikuu town, a sunny place with little rain, full of silly people who act out silly little events".
If that was his goal, he has succeeded beyond doubt. And drew a darn funny manga called Angel Densetsu in the process.
As for the ending, it gave more closure than most manga manage to be honest, the obvious parallels between Kitano/Ryoko as a couple and the backstory of Kitano's parents serve as fairly blatant forshadowing for their fate at the very least. Then there's the chemistry between Ikuno and Takehisa, which has the potential to be something more than rivalry, and then Kuroda had that one moment of gallantry with "Ryoko's Friend A", Ikuko so... that could, potentially develop to a possibility of them getting closer in a non-descript manner...
In the end the main couple get together, while the others memebers' relationships are left to intrepertation, which is good enough for a comedy manga that doesn't actually focus on romance. Ties it up better than quite a few other manga I could name at least :p