Rating: 4 / 5
Light. Warm enough; add a thinlight or torso-length inflatable when it gets cold.
Comparing the NightLight's R-value to other pads, it appears that the Nightlight has the highest R-val for its weight, normalized to the inch. Even insulated inflatables and self-inflaters don't come close. Bulk is the main downside of this pad, IMO, particularly if one wants to use it in the pad sleeve of a pack.
I give it a 4 b/c it doesn't serve well alone, in colder weather and it is a little bulky. It would be nice if it could be folded similar to a Z-Rest. However, on the plus side, it is warmer, IMO, than the Z-Rest and definitely more robust as the Z-Rest compresses and deforms rather easily in comparison to the NightLight.
So, it might be nice if a thicker, warmer version of 3/4 length NightLight pads were made to extend the lower range. How to do this w/o adding too much bulk is the issue.