Firstly note that F4TFS is in 2 parts, and although part 2 appears to have been published at the end of 2010, AFAIK it appears to be unavailable right now. I have read F3TFS, and am going through F4TFS at the moment. Using Flex 4, available free as a 32Mb PDF, is a very useful reference, along with the 12 or so other Flex books available free from Adobe. While Using Flex 4 is a reference (including plenty of example code), F3/4TFS is structured as a series of lessons, working on the same project (Flex Grocer shopping cart app) throughout. It touches on most aspects of Flex development, and is a great guide for beginners. If I have one criticism of the book, it is that a shopping cart example is going to be inherently dull- so if you have a low boredom threshold you will have to force yourself through the examples. I would still recommend it as a beginner's book, although in the real world you are unlikely to be using Design Mode much, except for throw-away prototypes. If you have a project you want to get started on right away, then you could just wade in and start coding using the Adobe documentation for help, but if you'd like to have an existing example, then F4TFS is for you.
When learning Flex its best to read as much as possible, so I'd widen your reading if possible to include the Flex 4 Bible, AdvancED Flex 4, Enterprise Development with Flex, etc, and the absolute shedloads of blog posts and examples on the internet.