As an active person on both (and a mod here), Mastodon is definitely the most active. Yes, you have to follow liberally, dive into reblogs and follow some more, also cruising the Explore/trending section helps but it doesn't take long to build up a super fun feed. People engage alot, no algorithms, it's all just live and great.

Lemmy "elegance" isn't that elegant. I've had to work with admins to help break through issues of posts federating around, but it's getting better. I'm finally getting things going pretty smooth and my community is getting momentum, !AlternativeNation@lemmy.world but it's been a very slow, buggy, and painful process. One thing that helped was posting to my Lemmy community exclusively through my Mastodon account for a while to help bring people over.

Search is a wash. Mastodon, I can put a link to a post in the search and it pops up, can't do that here. But Lemmy has better search for just text.

You see? Both are nowhere near perfect, both are flawed, and both are great! They serve very different purposes and don't compete. They complement each other. I'm super happy we have both and absolutely love building up this community supported DIY fediverse.

Exciting times ahead!