As I review these books, it's important to understand the perspective, (and yes, bias) from which I approach my reviews. I am primarily a middle-school teacher who has taught ukulele in a class setting, and am still looking for a good method book that fits the criteria that I'm looking for.
There are a couple that come close, but here's what I'm looking for in a class method book:
A clear, methodical method that gradually build skills, but move quickly enough to keep the interest of the students
Contains short exercises for building skills & reading, in addition to longer "benchmark" songs
Focuses on reading music, NOT reading TAB
Is primarily geared toward Re-Entrant (High-G) turning
Contains some duets & trios as part of the progression of skills
Includes chords only after introducing at least the C Major Scale
Gradually builds strumming skills that emphasize strumming as a function of rhythm that can be written in standard notation
Emphasizes practice skills throughout the book, along with specific tips on how to practice
Makes no mention of Tiny Tim (Only slightly tongue-in-cheek)
Treats the ukulele as a legitimate instrument, rather than a novelty (See #9)
I understand that these criteria will not necessarily be important to you, especially if you found this page as someone who is looking to learn ukulele on your own. These reviews, and this website in general, is geared specifically for the classroom teacher who is teaching in the schools. I think many, if not most, of the books that I have reviewed can be just fine for personal learning, or private instruction learning.