Is this like an offline version of ancestry.com or familysearch.com?
I've used https://github.com/Linekio/getmyancestors to export data from FamilySearch and browse in Gramps.
I feel like there's an opportunity to do automated data quality assessment, and to provide some indication of that in the UI/with the data.
Overall though I'm fairly impressed with the fluidity of the UI and speed of the site, would be curious to know about their backend.