Few modern stoic texts have influenced my understanding of the philosophy more than Pierre Hadot's The Inner Citadel. I've heard the book referred to as a study of Marcus Aurelius' Meditations. It is that, in part. However, Hadot's deep knowledge of ancient thought makes it much more than an explanatory text. He expounds on Aurelius' words. He shows the influence of earlier teachers, and illuminates what seems to be uniquely Aurelius. More important to the stoic practitioner, Hadot takes a bare philosophical framework and fleshes it out. The Inner Citadel presents a livable philosophy. Hadot brings out ideas that can be locked within the original stoic texts for years if a student is left to personal reflection.
This is not to say that Hadot is a sage, or that all his thoughts are unimpeachable. Not at all. However, his work serves to elevate the discourse surrounding Stoicism. I find myself continuously returning to his chapters on the Three Disciplines, which alone make the book indispensable.
So yes, I like The Inner Citadel. I do not suggest handing it out as a gift for people new to the philosophy. It's not that sort of book, unless your pal is really into wisdom literature in which case, go for it. The Inner Citadel is for those of us who already practice stoicism in our daily lives. For us, it can expand our knowledge of the philosophy and assist in shaping our inner discourse.