It was simple, interesting, heartfelt, and satisfying. Gaiman has a penchant for endings that don't really live up to what I want from an ending, so I'm not surprised you had trouble there, but for me his strength lies in his simple, charming writing style and his fun, mythology-steeped characters. Graveyard Book is one of my favorites of his, along with Stardust, Coraline, and Neverwhere (and Sandman of course, that pretty much belongs on its own untouchable pedestal).