Good luck to them but I'm sticking with Rchain if I become a stakeholder at all. I don't have confidence in their centralized servers approach at all.

Blockchain is just a data structure for storing hashes but honestly for a social network a DHT would make plenty of sense for the data storage or even integrate with IPFS. Currently after looking Greg I would think Rchain is the one which could compete with Steemit and Ethereum rather than Synereo. I think developer talent goes a long way.