If you are looking for a balanced evaluation and comparison between Akka and Orleans, have a look at https://github.com/akka/akka-meta/blob/master/ComparisonWithOrleans.md.
The core message is well described in the introduction;
The most interesting aspect is the difference in primary focus between the two projects:
The primary focus of Orleans is to simplify distributed computing and allow non-experts to write efficient, scalable and reliable distributed services.
Akka is a toolkit for building distributed systems, offering the full power but also exposing the inherent complexity of this domain.
Both projects intend to be complete solutions, meaning that Orleans’ second priority is to allow experienced users to control the platform in more detail and adapt it to a wide range of use-cases, while Akka also raises the level of abstraction and offers simplified but very useful abstraction.
Another difference is that of design methodology:
The guiding question for Orleans is “what is the default behavior that is most natural and easy for non-experts?” The second question is then how the expert can make their own decision.
Akka’s guiding question is “what is the minimal abstraction that we can provide without compromises?” This means that “good default” for us is not driven by what users might expect, but what we think users will find most useful for reasoning about their program once they have understood the abstraction—familiarity is not a goal in itself.
I have used both systems in the past and I can stand behind the message as brought forward in this article.