I was considering running two horizontally-scaling non-vendor databases: one for handling high volumes of read/write operations that can handle eventual consist

I was considering running two horizontally-scaling non-vendor databases: one for handling high volumes of read/write operations that can handle eventual consistency and one for handling lower volumes of strong consistency/transactions. Would CockroachDB be a good contender for the strong consistency case (and who would be good competitors and why)? Also, I've so far considered Cassandra and HBase for the eventual-consistency option; any recommendations there?