[strmpnk]

Exactly. In terms of fault tolerance, a buggy actor is isolated in regards to scheduling others. Bad behavior has a more limited scope.

This isn't to say that one can't create a process that eventually has harmful consequences to the entire system, it just means it's much less likely. These little points of isolation add up. Scheduling, memory management, lifecycle, crashes, &c... It's why it's a bit funny when I hear Akka compared. Akka is quite impressive but I'd never consider it a true alternative to an Erlang or BEAM style runtime.

[atemerev]

Akka is quite good in terms of reliability (I developed in both Akka and Erlang). All actors in Akka are supervised by default, and restarted if any exception happens.

This allows skipping most of error handling in Akka code. If something's wrong, your actor will be restarted. Works great!

[strmpnk]

This assumes failure is clean. Some failures are tougher, for example, imagine code going into an infinite loop. It either system, you have waste but the scale of the disruption in Erlang is kept isolated where Akka would fail to release the thread. Otherwise, I'd definitely agree that Akka handles vanilla failures just fine by using supervision trees.