The handlebar clamp on my DC 300 is CRAP. I need to wrap a velcro strap around the camming clamp just to keep it closed.
Once that's taken care of, it's pretty good for my purposes, but for sustained (non stop and go) riding of more than an hour at night I take the L&M ARC HID. I hear the newer LEDs compare to the HIDs, but it was not so competitive a year ago when I bought them.
I think the 200 and 300 have the same output, but the 300 has the smart charger that switches over to a trickle charge when the battery is full. I'm not sure what other differences there are...