Three big differences in comparison with Erlang:
1- Cannot externally kill a process (yes, ergo process have a Kill method but the process will be in a "zombie" state until the current message handlers returns... maybe stuck forever)
2- No hot code reloading.
3- No per-process GC.
No per-process GC (still
very configurable) but for hot-reload, if you don't mind a completely different language, there are Akka.net and Orleans:
https://github.com/akkadotnet/akka.net
https://github.com/dotnet/orleans
Of course... if you don't mind a completely different language and runtime stack... there's always Erlang & Elixir!
This is true, but they come with a different set of tradeoffs w.r.t ecosystem, tooling and performance (which turns into per-node efficiency in this case). There is also a matter of comfort and team/personal preferences.
What do you mean by per-node efficiency?