In my project of working through early Greek philosophy, Heraclitus is definitely the first philosopher I've encountered that I feel is truly impressive and a thinker that like, modern philosophers may still have to contend with in a real way. His style is best described by his line "The lord whose oracle is in Delphi neither speaks out nor conceals, but gives a sign." When Heraclitus expresses his truth, he doesn't just express it outright, but instead gives us mystical and sometimes baffling indirect statements. His writing is passed down to us mostly in just aphorisms, one or two sentence lines that are often paradoxical and very finely crafted. By disguising his truth behind these poetic tactics, reading him isn't just about finding out an interesting new perspective on life. It's like a puzzle box that actually challenges the reader to figure out the truth for themselves through chewing through the sentence. His ultimate conclusions rest on the paradox that the world is forever in a state of change, but that it is through this process of change itself that the world is able to be unified and ordered. "On those who step into the same rivers, different and different waters flow." A river, like the world, is only able to be a river because it is constantly in a state of flowing. On a big picture level, really cool and honestly still believable and compelling.
Kahn's approach to interpreting Heraclitus emphasizes the philosopher's skill as a writer and poet. Arguably, Heraclitus is the first philosopher to care about things like word choice and sentence structure, and implicitly from this to devote attention to how his audience would receive his work. He comes off both as an elusive mystic and a creative perfectionist. He deftly references back and forth across his aphorisms, building a tightly interlinked web of resonance. In his most paradoxical or cryptic statements, I even pick up on a kind of contagious delight he had in frustrating his readers. As far as the translated passages themselves, I totally recommend reading them and looking at the commentary for any entry that you're particularly curious about.
Where this book falls apart a little more for me is in the translator's analysis. The positive: I like that Kahn reorganized the aphorisms into what their potential order in the overall now-lost book would have been, rather than keeping them in the random Diels order. His argument that a random order is, in its own way, still giving the fragments a certain ideological slant, is well taken. I also think that the angle which approaches Heraclitus as a radical new kind of philosopher who is as much a writer and rhetorician as he is a thinker, the first to really compose his writing, is cool.
However, for the general reader, which at times Kahn is openly trying to reach, getting into the swamp of Ancient Greek grammar, etymology, etc. can be a bit alienating and dry.
Also, and perhaps this is just an issue latent in looking at Heraclitus, because all of his doctrine is ultimately very (and deliberately!) intertwined into one big thesis, going through each aphorism in order and providing an interpretation of each, especially in the case of Kahn who really believes a lot of these fragments are expressing the same thing in different ways, is redundant to the point of total fatigue as a reader. I think about 200 pages in I got the gist and was ready to be done with the book, and aside from a couple interesting looks into word choice or little insights on contemporary Greek culture, I did not get much new perspective on Heraclitus' thinking the further I trekked into the book. Also, even if it's potentially not as accurate of a reading, the more "flux" interpretations of Heraclitus are to me just way more exciting and compelling than the strictly monist readings like Kahn's. He dismisses a lot of interpretations that I had read in other sources and found pretty cool, which leads to a more boring, even if convincingly argued, look at what is definitely the most interesting philosopher I've encountered yet. So yeah, not necessarily worth reading cover to cover, but I still appreciated Kahn's exhaustive insight and Heraclitus is lowkey an awesome writer.