Yeah I did, and I enjoyed it. The retro art worked for the most part, and my only complaint is the voice change for Batman, but even that kind of works considering the setting and all. It manages to be true to the visual look of that generations comics without sacrificing story or characterization. There are a number of cameos by various classic heros like Adam Strange, The Blackhawks, and challengers of the fantastic and they all have role to play in the tale. Persoanlly my favorite parts of the movie delt with the Origins of the Martian Manhunter, Hal Jordan's Green Lantern, and the Flash. Seeing the things they had to deal with and what motivated them to become heroes, especially in a post McCarthyism America, was actually pretty cool.
All in all I'd recomend this to any comics fan.