Just a note on the fog issue:
I see no advantage to incans in fog....my LED work better, and I have many of both to compare. There are of course poor LED focusing examples, just as there are poorly focused incan examples, but there is nothing inherently superior to an incan's light in fog.
The cd is the primary factor, as far as the light itself. If you have a blue light special led, or an incan with blue light, etc...sure, blue sucks for fog....but, white light, according to tests, is best in fog, with some yellow versions being acceptable. As you can get yellower LED or incan versions, its not the incan vs LED light, its the tint and cd, etc.
So, a particular LED, or incan flashlight, might be better than another, but, that's going to not be apples and apples, and those who feel the LED is better might try a different incan, and those who think incan is better can try a different led for comparison, etc.