I used Lemmy for a while but now I am planning to exclusively use kbin. It appears to be a way more mature project and is infinitely better UI/UX wise than Lemmy. Moreover it's a project maintained by a fellow Polander and not a bunch of tankies.
As it's open source I wouldn't look down on people using Lemmy, but if you are going to use it I'd recommend staying away from the main server/lemmy.ml.
I chose Kbin myself because it's way more like old reddit and I wasn't jazzed with the devs of Lemmy.
PWA is pretty okay but I am sure we will get awesome native apps in the future. I hope devs of Apollo, Sync and others will join kbin as it would be mutually beneficial as I am sure people would gladly pay for their awesome apps and at the same time it would attract more users ti kbin.
This. Basically googled what the difference was and the article I found said the lemmy creator simps for the USSR. And I have about as much as interest in a platform like that as I have into on created by Nazis.