I didn't mind the Sentinel, but this was was so different from every other Reacher book that it was jarring. By page 20 I was asking myself what happened: Was Lee Child still involved in Sentinel but this one was post-handoff to Andrew? I was tempted to go find some of Andrew's writing and see if it matched up. The writing was stilted, very short abrupt sentences, and the story line and characters were difficult to follow. The tension never really built, unless you count the ten pages where Reacher figured out the ultimate plot. But there was no buildup to that point. It came out of the blue. I don't know that I'll read any more of these. Well, since I've read all 26 I probably will, but from the library.
Suggest that the book go back to the editor. The bare bones of the story could have been so much better. It needs plot and character development, and much more polished writing.