If, as Rym and Scott say, Watchmen and Dark Knight Returns are the number 1 and 2 underwear pervert comics, then this is the third.
Basically, the principal is "What would happen if Superman landed in Russia during Stalin's reign and eventually becomes ruler of the USSR.
The artwork's really well done, and honestly has that Soviet propaganda look to it for much of the run; what really sets it apart is the writing, however. Much like how DKR isn't really a superhero comic, neither is Red Son. Basically, it's more about the drama and effects a "Super Man" could have on the entire geopolitical world. Yeah, Superman's crazy powerful it this story, but much like how he's stupid powerful in DKR, it doesn't really matter. What DOES matter is his interactions with people, and with Luthor especially. Entirely worth picking up and reading.