One of my favourite books. Didn't think it would be a book for me as normally I prefer my Trek set on starships, solving problems and discovering the unknown, but this was a page turner from page one. I liked how it weaved its way between the Cardassian episodes we saw on DS9, filling in some details and joining the dots.
It'll be a bit of both; I can only speak from my experience as a magazine editor, but you mostly hire people who you know from past experience are reliable, and then you can take a risk on a few promising new talents. If they let you down, you don't use them again, if they deliver they are added to the trusted regulars.