Overfiend - David Annandale Collection of three connected stories.
Orks are attacking the planet Octarius, and different groups of Space Marines have to blunt the invasion.
The White Scars have to investigate and stop the build up of forces on the moon.
Raven Guard are sent to the planet to see what the Orks are fighting for.
In space, the Salamanders have to stop the Ork space hulk before it reaches the planet.

They all also find that the Eldar are apparently working to the same cause, for their own alien reasons.

Lots of good action scenes, an infinite amount of Orks, and decisions to be made by each chapter regarding whether to work with the Eldar or try to stop them as well.

Each of the Marine Chapters are well described by the things that make them different to the others. The overall story really gels together.

Some of the Space Marine Battles books that focus on one particular chapter can be a long slog through the list of names. By doing this book as separate but connected stories then it keeps it interesting all the way through.