This was an amazing, single issue. It ties into the bigger event of "Dark Nights: Death Metal," but I thought it was a beautiful story in its own right. In fact, as I type this review, I have finished the main series, and I didn't feel like I was missing much by not reading this as part of the series, however I would highly recommend this issue to fans of DC Comics.
A few years ago, I read Superboy-Prime's origin story in "DC Comics Presents" Issue #87, and this "Secret Origin" story goes back to that origin story, and gives us more material from between (and within) the panels.
As single-issue stories go, this was my favorite story that I've read in a while.