As with all the Amber books, the amount of lies, treachery, and deceit reach dizzying levels. Sides get switched, then switched again. Villains are revealed. Fates are decided.
Like so many fantasy books of the 70's, there's a big battle at the end. To his credit, Roger makes this battle plausible. The forces of Amber have been planning this counterattack for three books. There's no sense of "let's invent an army fast." Quite the opposite, he sets the stage for a truly titanic battle, complete with multiple generals under the brilliant tactician Benedict.
If you've been on this hell ride so far, you either love it or hate it. Most likely, you'll love it and be satisfied. If you've hated the ride to this point, you'll be well rewarded by reaching the end and never having to look at these books again.
The overall writing skill of the novel is notably better than Nine Princes. Roger has certainly developed, but don't be fooled. This is still very raw writing. There are places in the book well paced and engaging, and other that fill like filler. Given how short the book is, having sections that feels like filler is an utter crime.
On the whole, I respect Roger's imagination here, going where no other fantasy had gone before with its ambiguous politics and political backbiting. I can imaging George R. R. Martin sitting down with Roger over a few beers and getting some pointers on his future books, A Game of Thrones. Yet, I am also the first to admit that there are enough stinker parts of this series that it's claim to fame rests on its rawness, not its refinements.