This book almost got a one- or two-star rating from me, saved only by the comparatively frantic and action-driven second half. There was a really terrific fight scene between Dalt and Pattern-ghost-Eric that helped out a lot in warming me up to the book, but overall I felt like the Pattern-ghost device was rather cheap and overused. Zelazny thankfully did away with four-page descriptions of Shadow-walking in this, the last of the (true)Amber novels, but unfortunately he replaced this with an extremely powerful magic item that essentially lets Merlin do whatever he wants and kick everyone's asses. I liked Frakir better.
This didn't feel like the end. I know that other reviewers have already said that, but I didn't read their reviews before reading this or any other book in this series, and I thought the same thing upon reaching the end. The end of this book, and thus the entire series, was, to put it generously, a bit of a let down. An okay ending, but not a great one, whereas the series as a whole had moments that bordered on brilliance, which probably made the ending seem worse by comparison.
My recommendation to others: if you're a completeist like me, read all ten Amber novels. There are enough good parts in books 6-10 to warrant a read-through of the entire thing. If you're the impatient type, though, just stick to the first five, and let Corwin be your final memory of Amber.