I've been riding dark country roads with potholes and no street lights at all. And lots of hills. On 23mm tires. I've been delighted with the 200L under these conditions. It replaced a Cateye EL-500 and a PB 5000x (3.5 watt halogen). The 200L blows them away, no comparison at all. I also bought a Planet Bike Blaze for a helmet light (which is much brighter than the EL-500, and cheaper too) to help see around corners since my 200L is on my handlebars.

My average times are only about 1 to 1.5 mph slower than during the day on the same course. On descents that I usually go 35 mph during the day, I top out at about 28 mph at night (the only difference being I don't brake during the day but do at night). Other than that, I feel confident with this amount of light, given that I'm nearly always under 20 mph anyway. I can't imagine how bright the 600L or Trinewt lights must be.