Mostly, (reading Cadillac Escalade and Audi A6 forums) LED low beams are not as powerful as new HIDs. Current LEDs still have hard time matching HID systems in lumens per watt output (efficiency).
on the over hand LED are more intelligent (check 7-series LED headlights in action), last longer, output doesn’t decline over time like HID bulbs and they look waaaay cooler (at least Audi's headlights).
Originally Posted by Gray_Panther
Do they provide more lumens than HID?
I.e. more light output?