As the author of one book on screenwriting and another on filmmaking (The Portable Film School), I'm always wary of the competition. To be honest, there are lots of good books for new or newish screenwriters. None of them are really bad. It's just that some are really good. Superior.
All how-to books on screenwriting pretty much say the same things, but in different ways. It's like there are 100 books on Italian cooking, but at the end of the day, the recipes they teach are all dealing with the same ingredients. The key is the author of the Italian cookbook. He or she has a uniqueness, a certain style, a way of making difficult tasks seem easy or a way of making an experienced cook grow.
Viewing screenwriting books is the same. Some writers need lots of handholding, others want to be motivated, then there are those who like tough love. Whatever a screenwriter needs can be found out there. You may have to go through a few books or ask friends for recommendations, but you'll find 2 or 3 that will be a good fit.
"Writing Movies for Fun and Profit: How We Made a Billion Dollars at the Box Office and You can, Too!"by Robert Ben Garant and Thomas Lennon delivers on several levels. It's informative, entertaining as hell and gets into the craft of writing screenplays in a way that inspires. I've been a fan of these guys since Reno 911. I think Thomas Lennon is an amazing comic actor. I've heard him (and them) interviewed and these are two guys who know their way around Hollywood. This is a very solid book for any screenwriter.
As I said in the title of this review, their book isn't as good as mine, but it's damn close. BTW, they are not paying me anything to say all these nice things.