How does the genious guide compare to the LGB?
I've only skimmed the LGB, so the best I can give you is a review. It's about 200 pages and uses 12 games for practice. It is well written, reinforces the concepts taught and I found it very engaging (which I cannot say about most LSAT books). The author stresses that there's no "right" diagram just what works for you. He emphasizes diagramming based on the variable that changes least. He strongly de-emphasizes deductions but does discuss them and where he feels they might be appropriate - his thought is that most of the time you figure out what you need to know as you work through the questions while making unnecesary deductions costs time. There is also a specific order to answering questions and choosing games which makes a great deal of sense, especially if a person cannot complete all of the games. The book is broken into beginning, intermediate, and advanced techniques, which build on one another; you could manage games using any level of technique. Each game is thouroughly reviewed using the books techniques. At $35 with s&h it's a bit cheaper than LGB.
I used the book after 2.5 months of LSAT preparation and probably 200+ games under my belt...I still found useful information. The book outlined methods that it took me those months to develop/figure out on my own. The only thing it didn't teach are those mystical moments when you look at a game and know exactly how it's going to play out or when you look at a question and just know the right answer without thinking about it.