I have the 400R and I'm very happy with it. I made my choice based on the battery.

It has a mode they call Steady with Pulse Burst. With it the light is on low and flashes on high. It's 3 quick flashes then a short pause. It get's drivers attention because it's different and doesn't get lost with turn signals and other flashing lights. I don't see it listed on the Quad Red. I would check with DiNotte and if it doesn't have it I would go with the 400R even if you don't need the larger battery.