I am migrating from Syno Photos, which had been the greatest solution I had found, now to Immich, which is so polished and sharing is 10x easier than in Syno. The only gripe to Syno Photos is their implementation of Public/Personal space which is confusing and if you want to share something you have to store duplicate photos in those spaces. I used conditional albums to share certain faces with the partner and it has been OK.
Now it’s 100% Immich for me:
Clean, intuitive interface
Easy sharing
Very good face detection, better than Google (I compared the same pics I uploaded to both)
Easy transition for a Google Photos user
FOSS, you’re in full control over the deployment
Machine learning container to tag pictures
CLI interface to mass upload
Both galleries claim motion photos support, but for me neither actually works. Immich claims iPhone’s Live Photos, which I don’t care for, but Syno Photos say that in version DSM7 support Android Motion Pics, that I could not confirm.