I think having already used Mastodon, albeit mostly as a lurker, helped, but I didn’t find it difficult at all to get up and running on Lemmy and subscribe to a bunch of communities.
On the desktop version, thanks to not having loads of useless scripts, ads and other “stuff” on the page like Reddit does, Lemmy’s interface loads quicker in my browser than Reddit’s and is more responsive. I have had a few hiccups with Jerboa logging me out of my account and images appearing too small to view, but in general, it works well - fast, clean interface, no distractions.
The one downside really is that the content that was (is, but not accessible) on Reddit is not here yet, but that will change with time. Still, the atmosphere is much better, and I feel much more inclined to post here as there aren’t the hordes of people waiting to tear someone down who has a different opinion (cough, Reddit…) So overall, pretty good and glad I finally stumbled upon Lemmy.
I think these are “nice to have” features rather than absolutely essential, but:
For 1. I could deal with just being able to download my list of subscriptions and upload it to another server. That’s the only bit that’s really slow to copy over by hand.
For 2. I think the main thing that really would benefit is the ability to search all active communities on all servers. The way it is now is alright if there are only half a dozen really active instances whose communities I might be interested in, but it doesn’t scale if there are hundreds of servers to check out. Probably the more important of the two IMHO in the long run.