Well, where I had hope following the faster paced denoument of The Dawn of Amber, I was pretty much entirely disappointed by the two following books which never seemed to live up to the possibilities promised by the last few chapters of the first and never really build any sort of depth to the characterizations, the politics, or particularly the first person narrator (a particularly loathsome offense in my not so humble opinion). Where the first half of Dawn felt like unneccessary retread the first half of Chaos and Amber felt like filler meant to pad the book to the page quota. Nothing really happens except perhaps a subtler rehash of the retread that was the first half of Dawn with the addition of bad attempts to prose-ify something of a description of the realms of Chaos. I'm not sure if this is just a sign of late in the process rewrites and reorganizations or if the author really was struggling that much to "start" the second book.
Tied to those same complaints are probably my biggest concerns with the novel. In this age of spell check automatons there is rarely a typo in sight, but it sometimes seems like it makes Editors all the more lax and miss more of the editing mistakes that actually matter (which is rather close to the same complaints Mark Twain made about the prevalence of dictionaries in the world of literature). I hate to mock the editing work when the editor is listed in the dedication to To Rule in Amber, but in the end the trilogy stands out as a superlative example of when books need editors. If the editor did in fact do enough work to warrant the dedication then I have to worry that the original drafts must have been nigh on illegible.
First off is the problem of amazing English sentences that don't make any sense outside of context and only make sense in context after several repetitions and turning your head sideways to think about the words that might actually be meant rather than the words on the page. I'm talking about way more than your usual "to/two/too" confusion with words being misplaced with other words that often are not pronounced anywhere near the same, much less appear in the same lexical category (as might be the case with some written language form of Wernicke's aphasia). I wish I had logged some of the worst offenders of this, but I didn't.
Second there was a problem with the books psuedologisms. The spelling (and apparent pronunciation) of many of the trilogy's pseudologisms (fake words) were rarely self-consistent, sometimes even just paragraphs apart.
Then there are the truly offensive editing errors: continuity errors and plot errors. I'm very tempted to draw a graph (or several) to show the amazing continuity problems with Trump decks across the Trilogy, and that's just the major example in my head. Several key plot points are seemingly forgotten a handful of pages later and at best I felt confused (when being told the opposite of what happened earlier had actually happened) and at worst I felt patronized (when being told the same thing again and again for several consecutive pages).
In the end this would leave the trilogy in the terrority of "mediocre fantasy that I probably wouldn't remember in a week and most likely would never re-read". As a supposed tie in with such a formative work for me as Zelazny's Amber Chronicles I'm almost insulted. I can't imagine recommending it to any serious fan of Amber and I could only see myself recommending it to people that have only read a very small fraction of what Fantasy has to over (such as those that only read Tolkien or Saberhagen or Jordan and not much else) as a weenie introduction to the much deeper and better written Zelazny works, just as I only ever really read Michael Chrichton novels so that when talking to someone that only reads grocery store novels I might be able to say, "Oh, you liked Andromeda Strain? Well, here's a list of ten better sci-fi novels in a similar vein you might find interesting."