Faster, smoother, clearly caches more aggressively so much less halting when scrolling, smaller fonts so more compact interface.
Both are so early in development though it’s basically irrelevant. Tomorrow Mlem could push a new build that includes their new interface that I’ve seen in the GitHub PRs and I’ll be back to that one. For now it’s just like Mastodon was, using all of the apps and seeing which one ends up fleshing out into a fully functional experience.