I must say I preferred it to volume 1. Superman's origin story has been told about a million times...but his early career as a superhero - not so much (though that has lately been remedied by Morrison over in 'Action').
This book was a great exploration of Superman's impact on the world, and the world's impact on Superman/Clark. The origin story (in whatever form) is about Earth coming face to face with this God-like alien being who claims to be their savior...this is the story of a time when the world has had some time to let the fact of that being's existence sink in and think - 'What now?'
Parasite wasn't the most fleshed out character in the world but he was a more than formidable opponent for Superman...forcing him to confront, for the first time in his life, vulnerability, both physical and psychological. Clark's comment in the end about how he marvels at the bravery of human beings who brave the dangers and uncertainties of the world without being invulnerable was a great insight into the character's thought processes...one which I believe has never been seen before.
Its interesting, in a way, how the evolution of Superman's role as a hero is depicted in this story, in that it's kinda the reverse of the learning curve Morrison gave us for the new 52 continuity. THAT Superman started out as a crusader fighting against the corrupt and powerful, a street-level hero dealing with the masses at a more personal level...and eventually evolved into the alien savior of the entire planet, who got involved in cosmic-scale battles. But here, we start with a Superman who's a bit of a detached alien to begin with, concerned with the 'big picture' and keeping himself away from human affairs...but by the end, he HAS decided to step in and set things right, to at least some extent, and has become the crusader and 'champion of the oppressed' he was back in 1938.