Tl;dr: Are you a Mage Storyteller? If yes, then you want this.
This supplement fills a much needed niche in the setting of Mage, that of the Node. Nodes have such potential for, er, magic. The official rules have so far left this potential largely untapped, stranded in the limbo between soulless mechanics and bland templates. Charles Siegel, of Mage: The Podcast fame, has put together everything you need to breathe life into your Chronicle's places of power.
You get a number of paradigms defining how mages see nodes, a collection of sample nodes, and a set of rules that'll help you build unique nodes by yourself. More importantly, this supplement helps you think about nodes in the way they deserve.
The overall feel of this PDF is professional and official. At no point do you feel like you're reading anything but a Mage-supplement. Yes, there's the odd typo or editing error, but this is a very reasonably priced fan-made supplement, so I certainly wont complain.
[5 of 5 Stars!]