Now there are no well-established parameters by which shardings are compared, each project has its own characteristics.
However, our CTO, Igor Belousov, proposed his classification for distributed systems with sharding. Below is a table comparing known platforms.
Note: not all information was published by some of mentioned projects.
If there is a main chain in the system, this means that the speed of validation of any transaction is equal to the rate of validation in the main chain - 2-3 minutes in general. There is an opinion that when there is a main chain, these are actually different blockchains combined in one platform, and not a single blockchain network.
State refers to all system parameters at the moment (all accounts, the amount of funds for them, smart contracts and their status). If the state is full (for example, in the Zilliqa project), all nodes must store all the information that is energy consuming. Easier validation here is the main advantage. Sharding state - each shard works completely separately, validation takes considerable time. We have a mixed state type. Part of the data (state of shards, accounts belonging to shards, state accounts, private shards, whick nodes are validators) is stored on all nodes. And the data that is processed is stored inside the shard.
Cross-shard transactions (between shards) - in most projects go through the main chain, but in our system - directly.