> * clustering - what kinds of clusters are supported? How do they scale? Do they favor availability or consistency?

There is no persistence so consistency is irrelevant. NATS does everything in the name of availability to the point of dropping connections for slow consumers.

> * security - is there any authentication? authorization for certain resources? TLS?

TLS is planned, not sure on timeline. It sounds like Apcera has plans for some form of authentication and multitenancy as well.

> * guarantuees for delivery? Transactional modes?

At-most-once delivery. No transactions. There may be some form of more reliable delivery coming in the future, but I'm not sure of the details.

> * what does the wire protocol look like? Support for meta data?

Very simple text-based protocol. I don't think it's formally documented anywhere currently though.