There are many biographies of Luther and this one is as good as any other, truly. I feel like Todd does a good job at keeping Luther right-sized. He was an amazingly productive writer and theologian, he effected great change throughout Europe and as the Reformation took root, he was aware of his place in it. Having said all of that, Luther wasn't quite comfortable with the world he helped create; he believed in a strong central authority, but rebelled against the greatest authority of the time; he believed in hierarchy, yet his works and life inspired peasant revolts (which he famously condemned); and he was at his heart, a private man content to spend time writing, translating and reading and yet he became the public face of a religious revolution that is still ongoing.
Looking back at my old notes, all of the details are in Todd's work, the key relationships of his life from his parents to his most trusted lieutenants to his most bitter rivals. Luther's life course brings an easy structure to the book as well, basically an academic's life punctuated by extreme public episodes, 95 theses, appearance before the emperor and the like. Todd's work is worth a look, even 30 years on from publication.