After some of the negative comments I was unsure if this would be a purchase or not, but for $9.99 on the PDF what do you have to lose? Then I was blown away. Regardless of what you think of the Shifter, the rest of the book is excellent, with plenty of new, exciting, and interesting options and additions.
As for the Shifter, I can see where some people would be disappointed, and would have expected something different, but for what it is, the Shifter is fine. They're not the end-all, be-all class for shapeshifting...that kind of class still doesn't exist, but they are a nature-based class, centered around taking on aspects of a chosen animal aspect, with new aspects chosen at higher levels. Some think the animal selections are too limited, but the introductory paragraphs before the aspects explicitly says these aren't the only choices...and encourages players and GM's to create their own. I have a feeling we'll see more Aspects in the future. The only thing I would change on the Shifter, is to give players a choice on their natural attack. I wouldn't make it claws only. Depending on the aspect I'd let them choose gore, bite, or slam instead, depending on what would be appropriate for their first Aspect. That's easy to houserule, and hopefully something that might get expanded upon with new archetypes somewhere down the line. Honestly, it's a little quibble.
Don't be scared away on this one, I think it's one of the best player focused books they've put out in a while!