In short, this book is the perfect companion to the main Traveller rule book for gaming groups looking for more options in their equipment list.
In fact, the first few dozen pages (an overview of technology levels, their impact on society, and the difficulties players will have working too far outside of their usual areas of expertise) is so relevant that it should have been in the main rule book. That also goes for the updated security and hacking rules, and the advanced equipment prototyping (and reverse-engineering) rules. Good stuff.
The rest of the book comprises the "supply catalog", and the preview's table of contents lets you know what you're getting in to. There aren't any real surprises here, except that the CSC goes well beyond the Classic Traveller setting, including things like "arcswords", "stun fists" and "psy-boost daggers", as well as a number of TL 17+ items such as disintegrator pistols that are well above Third Imperium tech levels.
In other words, not everything in this book is appropriate for the Third Imperium setting, due either to tech level or theme, so a Referee will need to provide some guidance on what is available in his games.
I've seen some complaints that this book is mostly "weapon porn", and I can't really dispute that. Just under 2/3 of the book is weapons and armor, though considering that the CSC covers the topic of weaponry and armor in detail from stone age to super-tech, that doesn't seem too unreasonable.
The artwork varies from classic "pencil and paper" outline artwork to a handful of amusing "magazine ad" looking pull-outs. Some of Mongoose's other books suffer from highly variable art quality, and while CSC is a bit schizophrenic in its split between classic style line art and sometimes video game or Anime-stylings (especially in the Battledress part - the Knight Sabers would not look too out of place in those suits [not a bad thing, IMHO]) but overall I found the artwork to be good. My only complaint is that it's not always easy to tell which weapon each piece of art matches up to.
[5 of 5 Stars!]