kbin definitely feels more... idk polished? compared to Lemmy. Lemmy feels like a proof of concept, while kbin feels like effort was actually put into it's UI. I bounce between both, but I certainly prefer kbin.
@ripcord Squabbles is very slick. I think it does a great job of meeting its mission statement of being a cross between reddit and twitter. I think if it can scale well (it's still primarily a one-person effort I believe) it has a shot at being a serious reddit/twitter competitor. And its user interface feels modern, whereas both lemmy and kbin feel like they're a generation behind in terms of UX. (I know many ex-redditors prefer the old.reddit.com look & feel by the way, which is probably why they'd more likely to be drawn to the current crop of threadiverse sites, but the casual user is more likely to be drawn to something like squabbles.)