Synereo is over. They decided to be closed source.
Rchain will use the Casper consensus protocol from Ethereum but then make improvements on where Ethereum falls short.
That kills it. Struggling team, no delivery on anything so far, now hiding the technology details from interested eyes. That's a no-go in crypto. The source must be inspectable.
I remember one advantage of k-something and rchain has been storing a blockchain in shards, or parts. At the current moment we have "light clients" that connect to somewhere else where a whole blockchain is stored. And sometimes some "pruning". AMP/Synereo looked so promising right before their 2nd ICO