While I am posting from a lemmy account (because I didn't know about kbin when I made it) if I was to host one of the two it would be kbin. The reason is that lemmy has some hardcoded moderation things inside it that I disapprove of. I believe I should be able to say anything I want without fear of being censored on my own self hosted instance and this comes from a leftist, I don't want to use bad words to insult people, but if I want to use them in a different context I want to be able to. If I see an argument between a bigot and a fellow lgbtq and the bigot calls my comrade with a slur I want to be able to describe the situation using the exact words used. I think maybe it's a cultural difference thing, where I live using slurs in a context where we describe a situation rather than for insulting someone it's not seen as a bad thing. We don't give those words so much power and importance to the point that even just saying the words makes people gasp. I believe that censoring some words by default without even considering the context they are being used in doesn't help, I believe it just gives the words more power while we should aim to take power away from them.

Also kbin has a much prettier UI in my opinion.