I don't think leds have great output to use as headlights. They are bright but don't have the output on the ground to go with it. I have Xentec slim ballast hids currently in the lows, fogs and regular ballasts in reverse. The new slims I bought are great. I can turn my headlights, or fogs, on and off many times with no delay or misfire at all from the lights (I kno u shouldn't do that, but that's what I do lol).
Me personally, if I'm upgrading the lights id do hid lows and led hi beams or fogs (hi beam if u don't use them to often)