Piefed has quite a few features that Lemmy doesn't have:
- multicommunities
- onboarding process asking new joiners what they are into
- crossposts comments consolidation
- communities moderation features
- posts and user flairs
- keyword filters
https://join.piefed.social/features/
Lemmy should get there in version 1.0, but they still don't have any precise timeframe for that release, and still need to do some testing https://lemmy.ml/comment/23570258
You might see a few people discrediting Piefed for some optional filters it offers, but all of those filters are configurable by admins and disabled by default: https://piefed.zip/c/fediverse/p/1005977/piefed-admin-settings-that-allow-to-enable-or-disable-content-filters-they-are-disabled-by