This book is awesome-sauce. That's all I have to say.
Okay, not really - like a lot of fans of the Breed books, I've been waiting for Jonas's book, and Lion's Heat lived up to all my expectations.
I won't say too much else as I don't want to spoil it for anyone, but I really think all you Jonas fans will love it.
If you haven't read this series, I wouldn't suggest starting with this one. The first mass market release was Megan's Mark and I think you can easily jump in at that point (that's how I began). However there are prior books in the series that originally came out in ebook format. You can see the complete chronology on Lora's site.