I like it! Main issue for me is that there is not enough content on my hobbies, and "all" content is mostly filled with reddit-this and lemmy-that (or now threads) stuff, which is annoying because I don't want to talk more about the platform than actually using it. But I hope this will change with some time.
I use only the browser, UX and UI is pretty straight forward, but subscribing to communities of other instances is really weird. I need to copy the "handle" (i.e. [email protected]), and add it manually to my instance domain (i.e. lemmy.world/c/[email protected]), and then I subscribe to it. I don't know if there are other ways (besides finding new communities via "all").
I'm not into the technicals of lemmy or the fediverse, but I guess this is not easily solvable, as an instance doesn't know that I am the user of another instance.
I also use the mobile UI. When I browse through a new community from another instance (but through my home instance) I just expand the sidebar at the top, and use the subscribe button there. No need to copy/paste the community handle.