I just watched this tonight via 35mm projection and while I thought the story was decent and have to give props to Matt Damon for carrying the entire movie (I think he was in almost every single scene) I did not like the look at all. like David, I too thought it was more 70's than 90's and going for a retro look that seemed lost between trying to give it a mood and being Grindhouse.
There were some shots that were way underexposed, in a way that didn't offer anything to the scene. One of them was a simple conversation in his house on the couch with just some back lighting from a practical light. The red tint to everything in the shadows (due to the uncorrected tungsten light) was not pleasing to me, only some of the daylight scenes looked decent.
Now I want to go out and see some more 35mm project RED material just because I can't believe this camera is that bad. All of the hype I've heard about the RED seems misguided after seeing this movie.