It's basically the separate volumes of Scots Armies of the C17th with a bit of tidying up and better typesetting. The Osprey is a simplified version of it.
It's possibly the best overview of the Scots in the Wars of the Three Kingdoms going. But then the field isn't exactly crowded.
If you want minutae then supplement it with Furgol's History of the Covenanting Armies (sadly oop, but it turns up on ABE from time to time at sensible prices). There's a volume by Furgol (I forget who the co-author is I'm afraid) looking at the Royalist Scots due out in the next year.