I finished this in less than 2 days. I think that's a record for a 250+ page book.
Valid criticisms of this book might include that it reads a bit like death porn, knowing as we do the ending, but those criticisms would have missed the boat (or ship, as it were). As Stanton himself explains in an afterword, his ultimate goal in writing this story was to explore the survivors: their ordeal, their suffering, their lives post-Indianapolis. How do you survive something like this? Naturally, exploration of this gives us insights into the human character as well as insights into war itself.
Clearly, the lack of rescue of these men was due to an extraordinary amount of bad luck (if 8 switches will save your life, and 7 of them fail, this is the situation you'll find yourself in). It also shows how much at fault the Navy really was in this disaster. It's infuriating to read and propels you forward in the story to the next unbelievable bit... and the next one...
However, what I would have appreciated at the end was a little bit more about how Captain McVay felt after he heard what happened to the largest number of floating men, as well as more about how the men felt about being survivors and the guilt that comes with that. I know Stanton must have heard the latter and I'm surprised at the lack of it in the book.
Regardless, it is beautifully written and for that alone it is worth reading.