Cool White
ad in: alot of light
ad out: Limited useability due to limited color rendition ability
Neutral White
ad in: Very useable, sufficient output for most tasks
ad out: somewhat insufficient as accent lighting due to adequate [but not superb] color rendition
Warm white
ad in: Very high CRI compared to cool white, wonderful light out in the woods or areas with alot of green vegetation.
ad out: Not the brightest LEDs [in XRE form] compared to NW or CW
To give you a good idea of the different variations from an observational standpoint, consider these pictures and the amount of yellow phosphor in each
Neutral White
Warm White
W100 "Q4" cool white
Generally, cool white is used in flashlights more often than not...so there's not really much preference in selecting tints. I personally use Neutral White and Warm whites in combinations for household fixed lighting.
I have a L4 modded with an [M bin?] 5A tinted MC-E and outdoors it is amazing. It rivals the tint of an incandescent and really breaks the long rigid perspective about the cold CCT nature of LEDs. Its pretty hard to describe the feeling, as if warm white LEDs aren't LEDs and fit in their own category. Since the beginning when McGizmo spoon fed us with details on the Nichia 083 parties of the forum has been raging on CRI for many months now...specifically in the effects of observing the world around us through improved color rendition.
Consider these series of shots
[1: CW on top, WW on bottom], Lights used: two MCE modified L4s on 17670s
[2: Surefire A2 on top, WW on bottom], Lights used: Surefire A2-WH, MCE modified L4
[3: CW on top, A2 on bottom]
the wall is very light green [there are no white walls in this house, or at least vacant white walls] and the cameras daylight balance may have distorted the tints. But you should be able to tell that the WW CREE is at least comparable with the A2's xenon with the absence of a central hotspot. In the picture where the WW is taken with the A2 the A2s beam came out very realistic due to the fact that the camera is not being flooded by the CW's intensity.
What the WC fail in color rendition is compensated by increase in intensity relative to WWs, so for many it doesn't seem that big of a change.
This example kind of reinforces the sentence in italics. The CW just gave out so much light that using a fully automatic camera its impossible to gauge rendition readings without the camera stepping back to protect its CCD chip. From left to right [Control][CW][WW][A2]
I hope someone with a manual camera can take shots outdoors, because thats where it really matters