Book is nearly everything Id hoped it to be, but I wont review because, to be honest, there are several other reviews out there much better then I could do. Ill just say I have found nothing to disagree with, having read most of it myself now.
The one thing Id not heard that I wanted to know was how the Red Scorpion characters changed things. So, here, have some info!
Sevrin Loth: He is a librarian model, first guess puts him roughly on power level with Tiguarius, with the ability (not requirement) to take an Honor Guard squad. Depending on the guys I play with, I might try to get him in a game or two. He does NOT affect your army in any real way (no Chapter Tactics).
Carab Culln, Lord Commander of the Red Scorpions: Not too many changes from the IA4 version, aside from a Orbital Bombardment as per a Chapter Master, and Chapter Tactics... For the Red Scorpions, Chapter Tactics is that they MAY give up Combat Tactics, and if they all do, you can replace Tactical Squad Sergeants with Apothecaries (as from the Command Squad). So, I can replace wargear options for FNP on my main scoring units. I will likely slap some Apothecaries together anyways, but in all likelihood, he will either be a rare choice, or used as a standard Captain.
Ive assembled the characters already, Im just trying to decide on the Honor Guard. See, they came with the full Command Squad sprue, so I could just make that up instead, and save the Honor Guard bits for later, when my force is better on its feet. Something to consider....