Bitcoin technology stack — especially when enhanced with sidechains and payment channels (such as from Blockstream and Lightning Network).
Ethereum platform — currently the second most proven platform, behind the Bitcoin stack.
Hyperledger Fabric — a result of significant strategic investment from IBM and many others that is reaching into an installed base of large corporate customers.
R3 Corda — vertical-oriented blockchain technology (the company prefers "blockchain inspired" because it emphasizes significant differences between this private/permissioned ledger offering compared to the public/permissionless ledgers such as Bitcoin blockchain).
Digital Asset — another vertically focused blockchain technology that has high visibility in the financial services sector
While it is very difficult to predict the eventual winner given that it may not even be on the market, but it is possible to state what that winner will look like. Here are the 9 characteristics of a winning blockchain platform
Open source — this is necessary to cultivate a rich and diverse ecosystem and accelerate adoption through network effect.
Modular architecture with layers of programmability and customizability — as above, this cultivates an ecosystem and enables market adoption.
Global scale — scalability, performance and efficiency are essential if blockchain is to become the foundation for the "Internet of Money."
Multiple implementations of the core protocol — multiple, independently developed implementations ensure that the protocol is understood, well-defined and adds resistance to possible attacks (as occurred with the Ethereum platform in September 2016). This requires there to be an accurate and precise specification of the core protocol, as opposed to relying on one codebase that is not documented.
Hardened through public blockchain deployment — this is the only way to ensure that the system is secure and "bulletproof," by exposing it to the worst threats on the open internet, as has occurred with both the Bitcoin stack and the Ethereum platform.
Configurable for private blockchain deployment and support for confidentiality of transactions — because most businesses do not want their transactions to be visible by their competitors or by the rest of the world.
Functioning governance — there needs to be a cohesive decision-making structure that can respond in an agile and coherent manner to threats to the system.
Advanced smart contract capability — because the current generation of smart-contract technology relies on traditional languages (similar to Java or C#), which are inadequate for the rigorous requirements of large-value contracts (and are best supported by metadata-driven or mathematically verifiable programming systems).
Adequate tooling for developing, debugging, deploying, monitoring and managing smart-contract-based systems (the importance of which was underscored by the recent denial-of-service attacks on the Ethereum network).
