TON is a multi-chain project with generalized support of all transactions.
Ethereum 2.0 is a major upgrade for the Ethereum blockchain network that is currently in development, also known as Eth2. It's designed as the Beacon Chain with up to 64 shardchains but only has limited cross-chain communication. Ethereum 2.0 is not yet implemented as of April 2022.
Solana is a single-chain blockchain project optimized to execute specialized transactions at high speeds.
Comparing TON, Ethereum 2.0, and Solana
Block and finalization time
TON generates a new block on each shardchain and the masterchain approximately every 5 seconds. New blocks on all shardchains are generated approximately simultaneously, and a new block on the masterchain is generated approximately one second later because it must contain the hashes of the latest blocks of all shardchains.
Ethereum 2.0 has slots and epochs. A slot is 12 seconds in which a new Beacon Chain and shardchain block can be proposed by a validator. 32 slots make up an epoch (6.4 minutes). There are specific rules dictating that block finality requires at least 2 epochs. This means a time-to-finality of at least 12.8 minutes.
Solana claims to generate one block every second or faster, but it has an extended block finalization time. A block is usually finalized after 16 voting rounds, with each round expected to last approximately 400 milliseconds. This means a time-to-finality of 6.4 seconds.
TON is a Turing-complete and high-performance blockchain that can accommodate any transaction complexity on a masterchain and all of its workchains.
Ethereum 2.0 has Turing-complete EVM only on the Beacon Chain with a network limit of 15 transactions per second. A lack of cross-shard interactions means additional transactions will not be executed in a truly decentralized environment.
Solana is Turing-complete, but it performs well only with a large amount of very simple transactions of several predefined types (which change only an account balance, not a state) and only when all the data of all accounts fit into RAM (and when it doesn't, the blockchain can face some issues).
TON supports workchains and dynamic sharding. The system can potentially accommodate up to 232 workchains, each of which can be subdivided into up to 260 shardchains with near-instant cross-shard and cross-chain communication, resulting in millions of transactions per second.
Ethereum 2.0 will support up to 64 shardchains and the Beacon Chain. At this stage, it is unclear what the exact capabilities of the new 64 shardchains will be and how the shardchains will interact with one another. However, if messaging among shardchains is ever introduced, one would have to wait for 10–15 minutes until the finalization of the shardchain block originating a message before that message can be processed on another shardchain. Furthermore, the additional shards are currently not supposed to be able to run EVM smart contracts at all. Instead, they are supposed to be used as additional data storage in a distributed ledger.
Solana has neither sharding support nor workchain support.