mondo84: All the books have positive reviews on Amazon.com.
The question is, who wrote the reviews?
Not that I wish to insinuate that the authors have been engaging in shady dealings, but if teenie girls with posters of a topless Taylor Lautner on their walls and little interest in intellectual stories have written them, then it's going to be of little interest to many of us.
For example, the Undersea, Bypass Gemini and Unstable Prototypes reviews do look promising, but the three-liner reviews from "Heather", "ona", "JenX" and "Scampi" on Journey to Hart's Halo are not inspiring, the first review of John Gone reads "An action-packed adventure for teens", and with Missing Signals being the sequel to John Gone, it's likely to have the same problems, and I've not been hearing good things about The Heretic either.
Still, I can understand the need to accommodate for different readerships, so I may yet consider this.