There are a few things.
1) It's non-toxic - that would've been a huge dealbreaker for me if it was toxic, because I have a history of unwittingly joining toxic forums (like LiveWire)
2) the mods always stay on top of whether or not there's a toxic troll (or group thereof) on here - back on the 1D forums, the mods were all lazy bums about trolls, and you literally had to message one of them just to get it taken care of.
3) the people are friendly - I find it very easy to make friends on here!
4) the events, like the card game and the User Awards - on KPF, the only events they ever host are the ones where you have to take a K-pop quiz. It was fun at first, but then it got monotonous.