This is not an attempt to convert Lemmy users, nor is it a slight on Lemmy. I'm sure there are plenty of reasons why Lemmy works better for some, and I love the fact that we not only have multiple choices, but multiple choices that allow us to interact with each other regardless! It's amazing. Lemmy is great, no shade.
With that said...
Why YSK: I see a lot of users posting frequent questions about Lemmy that are currently answered by kbin.
For example:
The ability to block a whole domain, or subscribe to one
The ability to subscribe to individual users
A built-in search tool to find communities all over fedi (kbin, Lemmy, Mastodon groups, etc.) with an indication of how active they are
Mitigation for the "tracking pixel" issue
I find that almost every day, I see Lemmy users asking about features and I think, "well, kbin does that." I think it would be worthwhile for more users to check into both platforms and decide which might be best for them.
Not currently, I think, but multiple are in beta and sending out invites. I use kbin as a rich web app and it works well about 85% of the time. Biggest issues are random log-outs, using the back button sometimes loses place in the never-ending scroll list, and there isn't a good way to see your subscribed magazines (you have to go to your profile and scroll to the subscriptions section to select it).
But I'm really liking Kbin so far. I'd rather not be on the instance that is hosting everything; just seems easier for it to get too big and fail quickly, and I'd like to stay in one location if possible. Kbin seems big enough to last but small enough that it isn't growing insanely quick. Another option is Fedia.io, which is a kbin fork. Very similar imo, just a little different.