I have the dualcross 300.
The first one I bought had a bad seal and filled up with water. REI replaced it, no questions asked, and so far the new one is watertight- I've ridden in some serious downpours.
I don't know anything about the technical specifics. My commute is an hour each way. The frame attachments are good and the cord is plenty long enough.
I ride part of the way on a bike path and my only complaint is that even on the dim setting, other cyclists have told me the thing is too bright and blinds them, so I have taken to just covering the light with my hand when passing cyclists coming from the opposite direction. Of course the cyclists complaining to me are also blinding me with their lights- in pitch black any light in your face probably seems too bright.