As a multi-protocol platform, Kaleido currently supports Ethereum and R3 Corda as protocol choices.
For Ethereum, there are three node client implementations to choose from for your permissioned blockchain: Geth, Quorum and Hyperledger Besu. Each client contains different protocol functionality (e.g. private transaction support) and configurable consensus implementations, allowing for individual networks to be built in accordance with consortia-level performance and privacy requirements.
For a deeper dive into the supported consensus algorithms, refer to the following blog post.
For Corda, you can choose between OS (open source) and Enterprise. Both versions support 100% of the Corda protocol, so there are no real functional differences between the two. The differences are non-functional, with the Enterprise version offering more deployment flexibility to meet the needs of enterprise security standards, notary clusters and support for Hardware Security Modules (HSM).
For a detailed comparison, refer to the Corda documentation.