I'm in the middle of the terrible ghostwritten books (the stretch I was remembering earlier this month), but there was a large (welcome) jump in quality from The Weakness to this one. I wasn't sure about the beginning of the book, but it gets better as it goes.
More discussion under the cut because it's all a little spoilery.
I thought it was laid on a little thick when the Animorphs were breaking up. I mean, it's pretty obvious it's fake.
I like the little details about Andalites. This is the book that mentions and Andalite warriors are trained to never focus all their eyes on one thing at a time (despite the fact that Ax has done so in at least a couple of books).
Ax does compare the new Andalites to bucks at one point which felt a little weird (would an arrogant Andalite really compare some of his own people to deer?).
Ax seems to have conveniently forgotten that Cassie, Jake, Marco and Rachel gave their DNA willingly so it's not the moral compromise he makes it out to be.
The collars along the infestation pier are an interesting addition. They make sense, and they left me wondering how much freedom the ghostwriters have when writing their books. How much of the story they're given and how much they get to add to it.
There's more, but I don't have my other notes with me right now. Maybe I'll come add to this later.