Eh. Lemmy has the biggest user base because it isn't a single site. That makes it hard for anything else to match. Since it's not being a single site also puts a barrier to entry, you get less idiots and low effort crap. Well, outside of the c/s where low effort crap is the point lol.
It feels the most like reddit with a lower degree of the bad parts. The differences tend to be beneficial or neutral rather than a detriment. The only real significant flaw is the early stage of development. There's a lack of feature and tool parity that's pretty big. Luckily, the boom in users hasn't gone very far past where other tools will be needed, and there's enough apps that are killing it in terms of features that make up for the lemmy development lag that it isn't something that matters enough to make going to a more centralized site worth it.
I'm repeating a lot from other comments I've made, but once discovery improves, and we get a solid organization ability for our subscriptions, you won't notice any minor differences at all. Moderation tools are weak, but they aren't necessary yet either. There's fewer assholes being assholey, and that's a huge factor that requires moderation more than anything but spam and bad bots. Mostly, the bots have been squashed on the admin side, so (again) there's no rush for mod tools like automod.
We need a flair system here pretty bad because it would make a lot of the issues with both discovery and filtration go away. Even a system would be useful, if it wasn't the markdown for headers.
After that, a lemmy wide search, and you've got everything essential from reddit that isn't already here.