I feel a bit cruel for saying so, but ENT:
By The Book and VOY:
Section 31: Shadow. I know both books are by the same writing duo, but these two books took me ages to get through...
To be fair, Enterprise had been on the air all of 14 minutes when
By The Book came out, so it's understandable that there are a few things not quite right, but I felt a bit more research would've helped the book. The actual mission seemed secondary to some RPG I had no interest in and the majority of main characters were sidelined for lowly crewmen. Also there was a lot of repetition, about setting stuff on tables and loud noises from bolts hitting tables, and Hoshi seemed to lose her surname...
Then there was T'Pol and Archer's conversations basically revolving around protocol. Protocol, protocol, PROTOCOL
Shadow annoyed me for a whole load of reasons

The repetition seemed to rear its ugly head again (a lot of people had hunches). Section 31's role in the story was flimsy at best - the redshirt woman who dies in Scientific Method planted secret instructions to kill Seven over a year later, a la Seska (Worst Case Scenario)... I fail to see how this assassination would have helped the crew of Voyager, much less Section 31 or the Federation on the whole.
Also, the computer seems to have gained some kind of semi-consciousness in this novel in order to pick out Seven, which struck me as odd.
Season 5 introduced the Malon and the idea that Federation technology is pretty clean by comparison, yet this book decides that Voyager has mass quantities of trilithium resin just sitting round ready to explode. Going by Generations, did they even know what trilithium was when Voyager was being built/launched?
And then there's the curious B plot - a civilisation decides to escape a solar system on the brink of destruction by putting all 800 million people on one conveniently cobbled together generational ship. Not a convoy, no, ONE ship carrying all the hopes of an entire planet. The descriptions of people living in the habitation areas lent nothing to the plot, and indeed, hardly featured at all towards the end of the book.
Some of the character's reactions worried me too, especially considering the book was written after the series ended, so it's not like we hadn't gotten to know the crew. Janeway, after spending 5 years (the novel is set just before Equinox) with the crew starts suspecting everyone bar about three people and openly mistrusting them (actually, can you mistrust someone?) - not very likely. Torres thinks the purple aliens are weird and can't really take them seriously. Hmm... very enlightened 24th century view
I've read a few books by Dean Wesley Smith and/or Kristine Kathryn Rusch. I don't mean to be so harsh or critical of their work, maybe I've just happened on two of their weaker outings?
Sorry about going on, they always taught me at school to give a reason for my answer
