So blockchain vs dags is coming. Blocks and tangles. Graph theory. DAGs are (directed acylic graphs). It's used a lot in big data technologies now like spark and tez and impala. But in the blockchain space you now have IOTA and Hashgraph doing more of tangles and DAG theory vs blockchains, but both these have detractors as in not much evidence they actually have a working implementation as they claim.
Time will tell.