Comment by trengrj

With Pulsar vs Kafka, I don't see a huge argument between either one functionality wise as they have so much in common (distributed log, Java based, avoid copying memory, use Zookeeper). Because Kafka is more supported and well-known it seems Pulsar needs to be an order of magnitude more performant to capture developer mindshare.

I see the same with Spark vs Flink in that similarities outweigh differences. I wonder if this is some sort of emergent pattern in open source software.