I like the 518 pages of grammar, that is about 1500KindlePages. For 9.99 you get a lexicon. I appreciate how it goes into the different Moods like the subjunctive mood of the verb has always been somewhat vague for me. There are a few parts of grammar in here that I have never even heard of. Also, it doesn't actually go into grammatical case like a rule of thumb but explains it as an adjunct to other things in the more modern English approach. However, even though it's not so prevalently important in modern English these days I still like to browse this particular part of grammar in my old-school books and then compare the newer way to completely nail it. All in all, you get your bucks worth with this book.
It has a concise set of examples and is useful when your are in doubt about a construction of a sentence. I would recommend it to anyone who has a grasp of the English language as a good prop. Although it i has a leaning to the American way of sentence and speach construction and not that of pure English, it is still passable.