There are quite alot of differences, no downvotes which means people can have freedom of voice without being afraid of flag wars and being bullied, no stable coin like HBD/SBD for a simpler economy. Blurt will focus on a mobile app and advanced governance features to prevent large stake from controlling consensus, Zapata will focus on dominating third world countries like Nigeria with a single country focus at a time.
Both have teams of enthusiasts who are doing it for enjoyment as well as profit, where there is passion, success will follow.