There is a new article "What's new in rotor v0.09" that tells several things about yet another C++ actor framework named "rotor". As for me it's a good example of how different implementations of Actor Model could be. And it's a good reason to write some words about SObjectizer's features to show how the same things were addressed a long time ago.
Before I start, it's necessary to note that some of the decisions described below are rather philosophical than technical ones. It also means that some decisions taken from philosophical standpoints had a significant impact on technical aspects of SObjectizer's internals and API, and on applications built on top of the SObjectizer.