Great motor racing movie, possibly the best non-documentary motor racing ever. (If you include documentaries, however, "Senna" takes it).
Excellent racing scenes. Every race was seat-of-your-pants stuff. Nothing was predictable: by the time of the last race there were still several possibilities open to how the movie was going to end.
The last race was one of the more intense 15 minutes or so in cinema history. There was a huge feeling of impending doom, but you did not know for whom (or even that it was for only one person).
Great cinematography during the racing scenes. It was like being there. Plus you get to feel what it is like to be someone in the crowd, or in the pits, or in the press.
However, the non-racing scenes detract from the quality of the movie. Yes, they show the private lives of the racers and make them more human, but they aren't done very well. The non-racing stuff doesn't develop the characters much, even though with all that time spent (and it is a lot) you'd think it would.
In the end the non-racing stuff just feels like padding, blowing out the running time and making it boring in stretches.
Good performances from James Garner and Yves Montand. However, nobody else really measures up. Jessica Walter was unconvincing and Eva Marie Saint, for all her talent (thinking North By Northwest), just seems a bit spare. Francois Hardy does a decent job, and looks stunning doing it, but has little screen time, or impact on the movie.