I use both Anime-Planet and MAL.

I joined Anime-Planet one time MAL had an outage, I think. Both sites have their advantages. A-P has a very rich database of tags, for both anime and characters, and also has a personal feed history that stretches back way longer than MAL's does. On the other hand, MAL includes metadata fields for when I started/finished watching something, and has some third-party sites that integrate with it, such as anime.plus, which I use to see stats on how much I've watched and when and how I've rated things.

So, for now, I just use both at the same time.

I once tried Kitsu, back when it was called Hummingbird, but I wasn't very satisfied with it. Haven't ever tried AniList or AniDB.