This book is very well done for what it is. A basic RPG book can only be so long before it become prohibitively expensive. One of the areas that is often neglected in the 'base book' is the stuff on how to be a gamemaster, narrator, whatever the particular system calls it. Mostly because on average, maybe 1/4 of the people who will read or play the game will ever run it. So yeah, SOME of this material appears in the main DS9 RPG book. But it is really expanded on so it is justifying its own existence.
Now, for someone like me who has been a forever DM and know how to do it almost like second nature, most of the tips you find in a book like this are fairly universal. Though there is quite a bit of stuff on how to make your adventures uniquely Star Trek. And even uniquely DS9.
But for someone who is either a newbie to running a game and/or newish to the Star Trek universe, this book could be a VERY big help in running a game.