It's not so much the telling of this tale that made it a worthwhile read for me. It is, as it likely is for most readers, the tale itself that is worthy of the read.
If I were to pinpoint the one thing about this book that struck me as ridiculous - and saints preserve us, there are so many ridiculous things about this case and these trials - it's the KKK in 1951 getting themselves together and drafting a resolution stating that they were opposed to the NAACP and the ADL because they were "hate groups." Flabbergasted is the only word that mirrors my reading of that particular paragraph.
I will say that I was not hugely enamored of the writing itself. Yes, it more than gets the job done in telling the tale of Marshall and his legal posse fighting and re-fighting these deplorable Southern cases, long before Marshall was appointed to even the District Courts. It is relentless in its description of the problems that faced both the black lawyers and the black workers in Florida in those times. In fact, what it does is repeat itself a bit more than necessary. (Yes, I remember that Marshall traveled extensively. Yes, I think I've had a decent description of McCall's clothing enough times now, thank you.) But by doing this King makes it far less likely that you will forget what he's writing about, so in that respect, it's worth repetition.
And, I have to give credence to the ending, because King pulls back in a number of loose threads that you may (or may not) have forgotten about, creating a strong, emotionally resonant final chapter to the entire story. It's worth reading just for that - but actually, everyone should be more familiar with what transpired in the 50s in the South. I'd call it required reading.