Before I started reading this, I was struck by how much it appeared to be like Michael Underwood's Geekomancy, and after reading it, of course there were a few similarities, but where Geekomancy was all delightful snark and nostalgia wrapped into a wonderfully magical system, Flex was a lot more dark and serious, and... 
 Shall I say it? Yeah. I have to say this was the better novel of the two. Sorry, Michael! I love your stuff, but this was just too sharp! 
 We can scratch out most of the nostalgia and jump right into a well-crafted tale. The hero is a damn surprising hero, too. Just hearing about what he did, I honestly wanted to cringe and go... "How is that going to be fun?" And then after reading him in action, all my fears flittered away as I began to realize that this is the freaking Breaking Bad of urban fantasy. Just being a clever and unique magic system is fantastic, too, but my god, we jumped, wonderfully, from a guy who uses magic to do paperwork into a brilliant drug dealer. And not only does it work, but it's far from being the best aspect of the book. 
 Look. We've got an ex-cop who was branded a hero for accidentally killing a 'Mancer even as he respected what he saw, turned his badge in, as well as losing a foot, to become an insurance agent. If that sounds boring, then stuff it. Mr. Steinmetz makes it work well. The core of the book is about people who focus so much on what they love that they become travelling black holes of universe-changing power that comes with it's own built-in correction system. 
 For those of us who've played and loved the Mage storytelling system, you're right on target. Mr. Steinmetz acknowledges his debts here and to Mr. Underwood. 
 MC Paul's arch-enemy was fantastic. Paul was fantastic. Valentine was fantastic. And my heart-strings were so thoroughly manhandled by his poor burned daughter that I wasn't sure I was going to get out of this novel alive. 
 Sure, it might just be another novel set to destroy NYC, but on the other hand, I felt utter joy in the reading. I literally couldn't put this title down for the life of me. It was magical. 
 It's true I probably wouldn't have picked this novel up in the first place if I hadn't received an invitation to read its sequel in Netgalley, but that's my own damn problem. I'm leased to be proved an idiot. Never judge a book by either its cover or its blurb. Flex is no sophomore addition to a crappy UF collection. It's serious and it's brilliant. 
 All you peeps who want magic systems and UF and seriously excellent character progressions need to go out and pick up this title. It's pretty close to perfect.