You can read it here, too:
The Annuals and the Superman Red/Superman Blue and Superman Forever one-shots aren’t yet in digital (and some of the non-Superman books that tied into the Millennium Giants weren’t carried over to the above collection either; however, those MG tie-ins are in the Millennium Giants collection), but everything else is there in reading order.
Speaking of Millennium Giants, feel free to chat about that in my Superman Blue thread, if you want. I don’t recall seeing any in-depth analysis of the Millennium Giants, and I’d be curious to get your thoughts on the tale.