I've done both for a few years now and do not find much of a difference. Two or three days of darkness does make the bud look a little frostier, potency remains the same in my experience. I do it when I can, if there are no other crops lined up to go into bloom.
My girl likes it for bag appeal, but she trims much better than me lol, so the little extra frost is more noticeable.
Since the plant is not producing sugars during the night, it is forced to break down the starch into sugar over the dark period and release CO2.
Theoretically, this should get the cure off to a good start as less sugar and starch in the end result means a better smoke and better potency since less of the final product is crap.