Which protocol should I use?
Understanding the use case is crucial for crafting this response. Hyperledger Fabric can be a great option typically for enterprise use cases where there are competitive or separate entities operating in one shared network. The presence of channels enables 1 to 1 interactions in this environment on dedicated separate chains that make this an attractive option for consortiums creating sophisticated communication flows involving sensitive data.
For the majority of other use cases, most any of them can be met by using Ethereum. Kaleido has solved the problem of private messaging within our Ethereum offering by using Kafka / encryption for off-chain data transfer and FireFly has streamlined this process even further with data exchange and its ability to broadcast or private message within your network. Outside of messaging, Ethereum is a preferred option for use cases that are tokenization-centric as it more naturally supports the deployment of fungible and non-fungible token smart contracts.
For a deep dive into the different protocols, please refer to our blog here.