Disappointing. Basically it was a very high-level summary of the SCSS README in a vaguely "cookbook" style. Didn't impart an organizing mental model or opinionated approach to web design using these technologies. The only reason this wasn't a one-star review was that the intro to Compass and Blueprint were somewhat useful to me. Still, I think just reading the READMEs for those projects would have been better. Sad to see the Pragmatic Programmers releasing this.
It's essentially a summary of the README. You don't learn much, if anything. It mentions Compass and Blueprint, but in no way it does them justice. There are a bunch of examples you can probably use for reference, but I find them overly simplistic to be useful for anyone who isn't completely new to CSS.
Write in short-to-the-point style. One page of explanation followed by one page of example code and output. Not reference but more like cheatsheet in a small book format.