Curious, how is Pony's GC superior to Erlang? Erlang's GC is already pretty quick (since the heaps are very small).
One nice thing about the Pony GC is it can GC actors that are waiting for messages but will never receive one. In some other languages I've used I end up with processes idling in a receive on channel living forever but never able to exit because nothing is going to put a message in the channel.