I use my DiNotte 400L as my steady rear light, even then it's on the medium setting, but it's nice to know that I have extra brightness in reserve. I also have a TL2000 light that I always keep in alternating mode( not flash) to help in getting motorists' attention, and still not be totally annoying. I've checked out my 400L in all flash modes, but my commute doesn't warrant that drastic type of rear lighting yet. My forward light, on the other hand, needed something more than 2 or 3 watts, especially with the typical US motorists I contend with on a daily basis, and a dual Magic Shine set up seems to be doing the job in reducing even more, the nightly "close encounters" on my urban commutes.