I have the third edition, and it is a great book overall. It is not perfect, and has several errors in the mathematics. I heard reports of this before I bought the book and it almost dissuaded me from purchasing. Having dealt with them first hand, I would say I'm extremely happy I went ahead and bought the book. I am no engineer, but have a good conceptual understanding of electronics. This book has dramatically improved both my conceptual and quantitative understanding. When I find errors, it is because I work through the math alongside the book, even if the example is already worked out, and my numbers come out different than the book's. The first few times, I rechecked and rechecked again to make sure. Overall, I find the errors in calculations do not overly detract from the book; just make sure you verify everything before you "use" anything and you'll be fine.
As for the new edition, I would recommend it based on the 3rd edition, but if you already have the 3rd edition like I do, I would only get the new one if after previewing it, I needed the new chapter subjects. As for depth, many engineers and experienced electronics amateurs find the book too elementary for their needs. As for myself, I say it is a perfect step up from anything in the MAKE series. The way the book is organized with chapter 2/3 having your math and signals explanations theory, and the later chapters being component type and application-specific, works very well for different reader needs.