This makes the second Shadowrun book I've read, and it was a good one.
I work in the computer industry in real life, and if I had to choose between a decker and a technomancer, I'd play the decker because it gives me the opportunity to pretend that all the cyberpunk tech in the Sixth World is based on logic the same way real world tech is. However, the truth is that Shadowrun's tech is science fantasy rather than hard science fiction, so technomancy, within the game universe at least, makes a heck of a lot more sense (by not being required to make sense at all). This book goes deep into what "resonance" is, how technomancy works and doesn't work, and more broadly how the matrix and AR work. If you want to spend time with the data of the Sixth World, this is the book for it.
There are a lot of characters in this book. Arguably, there are too many characters: two separate teams of runners, a few corporate teams, a greek-chorus in the form of a BBS, some baddies, and probably more. I found it a little hard to keep track of who cares about whom, who's on who's side, who's a technomancer and who's a technomancer who can't technomance, and so on. Eventually, I stopped trying to track the cast, and that worked out pretty nicely. It sort of all clicks in the end, and the stuff that doesn't just becomes part of the haze of all the crazy events in the story.
The important part is that it's a good story about some major power plays, and the story never stays on the course you think it's on. Really heavy on the tech, though, so if you're into Shadowrun for the stealth and guns and drones, this isn't that book. But if you like data centers, immerse yourself in Dark Resonance.