Unwired is, for those familiar with Shadowrun, the Matrix book. I like what it has done, especially the examples of security and nodes, processes and comlinks. The fiction is great, as is the art (I give you exhibit A, the cover for Augmentation.)
Like the other splatbooks Street Magic, Augmentation and Arsenal, there are additions to the character options as well as shadowtalk about how things appear to work in the fictional Shadowrun world. I have to admit that I like the fiction and then rules explanation set-up used in this book and Augmentation and Street Magic. Topics include the social impact of the new Matrix, an Idiot's guide to the Matrix as well as multiple descriptions of the Matrix. Also included is a re-inclusion of a lot of information veterans of VR, VR2.0, Matrix and Target: Matrix will recognize.
This book is also a re-boot and re-aligning of the technomancer characters. Basically, they are given traditions and mechanics that essentially makes them almost "mechanically" the same as magicians. The same information in Street Magic about magician options are included but for technomancers. I like the change, personally, although some may question the thrust of making the Matrix another astral space.
Is the book great? Yes, although there are 2 problems, one minor and one major, which are irksome, at least in the first printing. The minor problem is a wrongly labelled chapter devoted to simsense and reprogramming (the mental kind) which is called "sprites". It's a minor problem. My biggest problem, and one present in Augmentation and Arsenal, is the lack of an index. Shadowrun, for me, always had a great index as a saving grace. The lack of the index does put more weight on players or GMs having to remember everything or at least knowing where to look it up at. While this is less of problem with an eBook, it's the reason I'll give it 4 rather than 5 stars.
All that aside, I bought the book and I recommend it for SR4 players or Shadowrun completests.