The light pattern is the same as the halogen, marginally brighter because of the bulbs. And with Projector headlights, the pattern stays the same, and the cuts on the left and right of the main patter (tree, sidewalk, side of road area) stays crisp and sharp.
The biggest difference besides color and brightness i have had is the brighter (higher Kelvin) HID bulbs pushes the distance of the beam further then regular halogen bulbs originally did.
No complaints here, im using 6500k HID's a little more blue(r) then stock, but still the brightest white you can get (from what im told)
Complete stock look, i would go with 5500-5800k.
Just my $.02