600' in the distance? Mine go almost a half mile in otherwise lighted Manhattan at about 600 lumens. I have to turn it down when I face traffic, but most NYC streets are one way.

It's light out now until where I almost never ride anyway, so I probably won't be using my lights again until fall. By then there'll be some new versions to look at. At this point I'm more interested in efficiency than brightness. They are already bright enough, but if they'd last 2 hours on high off a charge of a 18650 battery I'd be happy. Either the LEDs or the batteries can improve, I don't care which.