As someone who first switched to lemmy, and then quickly switched to kbin due to rampant de-federation in the lemmy world, I say I just first heard about lemmy.
But, Kbin is much more modern, and spectating the changes done in the last days alone, it moves fast and attracts many developers while all lemmy 0.18 did was breaking federation with kbin. I can fully recommend the switch to Kbin, its that good.

About Tildes, it seems to be more of a clone of Digg in the old days.

I wouldn’t say defederation is rampant, but there were a few very high profile examples that hit right when people were new. Specifically, Beehaw/LW and Exploding Heads/everyone. Plus the whole thing about NSFW content and types.

While it’s true that many of the original devs have problematic views, it’s not really meaningful. The software is open source, there are tons of new developers (with varying views), and the code has nothing to perpetuate their ideas. In fact, they are pretty isolated on their own instance (Lemmygrad) since everyone defederates them almost immediately.

Besides lemmygrad and explodingheads which are truly legitimate cases, defederation just hurts everyone. New users just expect to sub to the communities they like on reddit. That includes NSFW because that simply is something people want, and it never was an issue on reddit. The whole discussion on larger lemmy is childish and prude.

And about the developers, lemmygrad is largely isolated, but lemmy.ml is not and those same tankies run that. In fact its also the only lemmy instance that blocks all kbin instances via blocking the kbin user-agent. The development is also still largely steered by those tankies.