Rabbi Sacks's book is a distillation of study that he and his staff did over the years. In each parsha, he finds an opportunity to explore how the Torah views successful leadership from a Jewish perspective. Sometimes it's through a positive role model, sometimes through a cautionary tale, sometimes through exhortation, sometimes through symbolism. Each essay is nicely compact, making its point and supporting it from the text; and each week provides a different perspective though which a holistic view of leadership emerges.
The main drawback to Rabbi Sacks's writing is that his voice has become familiar enough through his commentaries on the siddur, machzorim, and hagadah; his online divrei Torah; and his earlier books that at times he repeats ideas that he has already covered in more depth elsewhere (such as the theme of "the culture of guilt vs. the culture of shame") and sometimes he sounds like a parody of himself.
Despite that drawback, these essays enlighten the reader on a way of looking at what leadership means in the Jewish worldview.
Rabbi Steinsaltz's book is also a collection of divrei Torah that he has given over the years, along with new essays. He is very interested in the issue of the individual vis-a-vis the community, where community is sometimes defined as one's contemporary Jews, sometimes the broader society in which the Jew finds oneself, and sometimes the chain of generations that link today's Jews to those in the Torah.
Rabbi Steinsaltz's insights are keen, and carefully phrased in a way that lets each reader identify with the author --- for me, a Modern Orthodox reader with a primary focus on what Rav Slifkin calls the "Rationalist" perspective, the essays have enough grounding in psychological reality that I can appreciate them as recognizing fundamental truths about the human condition, without feeling put off by assertions of kabbalistic connections with which I have trouble relating. But I can easily imagine a more spiritually inclined reader (not even necessarily from a Chassidische perspective) perceiving different layers of meaning in the text.
Both books share a rare quality: Although they address the weekly parsha, ground that has been well gone over, both Rabbi Sacks and Rabbi Steinsaltz have found something new to say. I have come to look forward to my time with them after Shabbat dinner, and the discussions at my family's table that these divrei Torah have sparked.
I highly recommend both of these books.