I've been on vacation for the past week (to Austria) and ended up picking up this work by Stefan Kornelius (published in 2013). It's an authorized biography, so the Chancellor kinda gave her permission for interviews and for some friends and associates around her to make open comments.
It's a good read, but with some limitations. Openly positive? Yes. But it's hard to nail down any character flaws with Merkel other than she hates to give speeches and dislikes idiots to an extreme. The key negative is a very limited chapter on Merkel's youth, the years in college, and the period prior to getting into government.
There are a number of chapters which go into detail about Russia, China, the US, the banking crisis, etc. Each discusses the issues and how the Chancellor handled them.
Overall, I give it a positive grade, and it's worth reading. In fact, there's so much that has occurred from where the book left off.....that you could add two more chapters to the current book very easily.
The unusual feature of Merkel? I think it's the fact that she's not really a pure political figure. She's more of a university professor or scientist.....who had some interest in politics.....and just wandered into the field at the right time and bumped into the right people. She's an expert of debate and is more than capable at putting statistical data into an organized approach and getting you to agree to her reasoning (she doesn't come to agree to some big party agenda unless it makes practical sense). She also hates travel and won't stay overnight somewhere outside of Germany unless it's absolutely necessary. One should also note that she's not a crowd's person, or seeking any kind of glory for what she does. I suspect she'd be the last German on the face of the earth that you could accuse of corruption.
So, if you were kinda interested in Germany and the political side of the nation.....I'd endorse this work by Kornelius.