I think that a flashing headlights are much easier to see. Much more likely to catch the attention of a driver. My safety is more important then somebodys opinion. If they think it's rude then... Too bad. I have two lights mounted on my front rack which I set in a flashing mode and I also have a helmet light which I set as a solid light. My experience has been that, when going through intersections at night a lot of drivers don't see a cyclist until the last second... flashing headlights are much more visible.