If Greenlee intended to write a book to make textual critics happy, to compete with standards like Metzger and Aland & Aland, then he surely failed, and Elliott’s review is spot-on. But Greenlee didn’t do that. He wrote a book for the average person, sitting in the pew, with some basic questions about the text. Greenlee paints in broad strokes and gives general answers to the questions, which is what his desired audience needs.
Academics and textual critics can continue to nitpick Greenlee’s book, but don’t pay attention to them. If you need something on textual criticism for a basic layperson audience, Greenlee is your go-to book.