I love the layout and the personalization which Anime Planet offers, compared to the banal simplicity of MAL (My Anime List).
However AP really really loses out when it comes to their manga database. They have all the popular ones, sure. But upcoming mangas such as Hell's Kitchen and Megalomania are missing. Some of the manga I follow religiously have actually ended their run in Japan and only awaits translation.
Seriously, well it does represent the anime part, please don't neglect the manga too. It's like forgetting the roots of it all.