I have a dinotte (the one that takes rechargeable AA's) and absolutely LOVE it, but I commute in very dark mornings on roads where there isn't much traffic (or on very dark wooded trails). I understand the risk that the light might be excessively bright to drivers, but so far have only had wonderful experiences with it. (It is a helmet mount, and I try to make sure it doesn't cast up/out too far.)
A friend of mine at REI told me that he feels riding with the light has really changed how traffic behaves around him (probably because they're crying, "My eyes!). I have had improved luck with mine as well.
I love it. I got the light because I needed to SEE. I also have front and rear flashing lights in the interest of BEING seen.
2007 Trek 5000
2009 Jamis Coda
1972 Schwinn Suburban
"I rejoice every time I see a woman ride by on a bike. It gives her a feeling of self-reliance and independence the moment she takes her seat; and away she goes, the picture of untrammelled womanhood."
Susan B. Anthony, 1896