Durability. If you need to push messages that don't get lost, RabbitMQ is a pretty solid choice. In years past the clustering situation wasn't great and there was some potential for message lost and that seems to be resolved now with quorum queues, but the biggest different between NATS and RMQ is the durability guarantees and the at-least-once delivery guarantees that RMQ has. NATS is more like ZeroMQ in that it expects the subscribers to be online. There has been some work by others using that NATS protocol to create a Kafka-like system (written in Go, I believe) called LiftBridge. So if you like NATS and it's working for you and you want durability, take a look at LiftBridge.
That's right, but I think at least since both are listed on their website as different ways to run it that it should at least be considered a native feature at this point.
