Very mixed opinions on this book. My thoughts are a little fragmented - somewhat like the book itself.
* First and foremost, the book is fun. The setting is a huge potpourri of all kinds of different magical wackiness; at its strongest, the book takes those wacky elements, pumps them up to 11, and gives us incredible, kickass scenes.
* Gooseberry Bluff is cram-packed with unusual, inventive characters, used in interesting ways. There's a lot of great surprises to look forward to - just to pick an early example at random, the protagonist, Joy is "face-blind," unable to recognize faces by sight. This unusual disability shapes Joy's character and has some interesting consequences all throughout the book.
* The author has clearly made a point of celebrating diversity in his cast of characters. The mere fact of having a black, female protagonist with a disability drives home how absent such characters are from typical light adventure fiction. I sometimes feel this goes a bit awry - one character seems to exist solely to serve as a poster boy for genderqueer-ness - but mostly it's terrific, feeling very natural but still making its presence felt. To be honest, just seeing the bias go in the other direction for a change is awfully refreshing.
* The biggest problem I had was that the book feels awfully scattered. It jumps between very different elements so frequently, that I didn't feel like the plot or the setting were consistent or plausible. The setting balloons very, very quickly from "sleepy, second-rate college with a vague threat of mystery hidden somewhere" into a hysterical "OMG an epic reality-spanning battle is being fought and every single person on campus has a humongous, world-altering secret." It's fun, but it's also pretty ridiculous. I started reading a bit past half-way on the serialization, and I'm kind of wondering if the author was writing the novel as episodically as I was reading it - it didn't feel cohesive; it felt as though the author was making up something brand new every couple of chapters, and tossing it right into the mix.
* The ending - or rather, the complete lack thereof. The book doesn't conclude, it just has a brief flurry of action, then ends with practically every single one of its threads dangling. I was kind of shocked when I realized that this episode was the last one - it just didn't feel like a conclusion of the story, in any sense. I'm guessing the author might be planning sequels, but really, I'd like to know that the author's capable of tying up one story arc before I follow him on to another.
* There is an element of preachiness to this novel that I can live with, but I don't enjoy. There's an overpowering anti-authoritarian theme here which is never justified, just assumed to be correct - anybody associated with government is suspect; Order is inherently bad and Chaos is inherently awesome; anybody genderqueer is a saint while anybody who dislikes LGBTs in any way must be reviled in return; etc. etc. Bias in fiction is very hard to avoid, but in this case I felt like it stood out very strongly without actually being examined - neither to justify it by demonstrating how bad whatever's bad is, nor to temper it by providing limited counterexamples. In other words, the viewpoint gets somewhat cartoonish and soapbox-y at times. That's a shame - this is purely subjective, but the parts of the book when the writing manages to express the same viewpoint without getting dragged up on the soapbox, I find it much more powerful and compelling.
BOTTOM LINE: A book with much to recommend it, but also with some major flaws. I was happily planning to give it four stars until it completely and utterly failed to end.
Particularly recommended for fans of Jasper Fforde's The Eyre Affair: A Thursday Next Novel - the mix of fantasy action, covert operations, and lots and lots of different fantasy tropes strikes a familiar chord.