I said this before but:

Oh look, yet another Apache real time/batch/big data/stream processing/ingestion/workflow/whatever product.

  Apache Druid
  Apache Spark
  Apache Storm
  Apache Flink
  Apache Beam
  Apache Apex
  Apache Airavata
  Apache Samza
  Apache TEZ
  Apache Hama

It's basically a terrible joke at this point. There's no single Apache page helping you to decide which one you want, and they all seem to have such large overlap. Most of them seem to have bad documentation, and give the appearence of not really being maintained. This puts me off even trying to use them. If there's this much scope creep/NIH/reinventing the wheel happening across the board, I can't imagine how bad each product is individually.

Apache Kafka seems to be the only exception...