Well, they're not really zombies but more of a Van Vogt-tian space parasite infection 'natch. Filled with a gabillion inside jokes, several of which had me barking out with laughter, the dual-authors really know their Trek lore; and though their end result is completely disposable once the last page is finished the novel is well worth a read. Sure, the plot and characters are all unrepentantly silly but it's in a having fun with the cliches as opposed to making fun of them if that makes any sense. I mean what is Zombie Apocalypse but a total Kobayashi Maru?
The only disappointment with it I had was it barely scratched the surface on the whole notion of Roddenberry's optimism butting heads with Romero's pessimism -- an idea I felt deserved to be explored further. But! What we got is good enough and manages to actually exceed its novelty trappings while embracing them at the same time as it answers the eternal question: What will it take to make a cross-fandom relationship work? Alien Zombiegeddon. Beyond that? Only 250 pages and a quick read. Track it down and engage as soon as possible, Boils and Ghouls.