If you're going by reviews as a potential quality measure, the author of Zombiestan is a proven review-faker who got caught sockpuppet-blasting dissidents in the comments (forgot which fake account he was logged in under and responded as his own name using the "real" account; I love it when they do that). The entire saga over at the Amazon discussion boards in
this long thread here.
Also, it's your thread and you can do what you wish, but I personally wouldn't see the point of re-mentioning an official time-limited established print-publisher promo freebie that's already gotten its own thread.