It's awesome. It's definitely on the serious side, and it takes time to build. Actually, it starts out as like a series of shorter stories, a few chapters each, before it gets to the one about the MC who like totally takes over and it's just a manga about them from then on. And the art is if I remember a tad rough at the beginning--definitely develops as it goes along. But this thing is filled with massive emotional payoff, bittersweet but in the end optimistic "hhhnnnngggg!!" type goodness.