light entity brightness

so far i've always worked in the area of 100-250 for bright lights and <100 for dimmer lights/effects (e.g. to simulate the glow of the exit sign model)
however, when i was looking at the decompiled maps, i noticed valve's lights are usually in the region of 800-1400.
so what's the deal?
now i've never found the maps i've made to be dull/noticeably darker than the valve maps, but i'm curious as to what others use for brightness values.

as an example, here's a screen from cp_lumbermill:
the light entities in this room have brightnesses of 100 for the flourscent hanging lights and 80 for the wall lights.



similarly; reservoir's lighting - most are between 100-200.

there it's identical to badland's ambient

well truth be told, i have quite a few areas on lumbermill where i was using lights with a value of 400 in interior areas... and it was pretty nasty.

to me it seems anything over 250 just makes all the textures around it get to glare'y

is there any advantage in using spots over lights? (except when you need a cone of light of course).
i use lights for shaded lamps too, and i think it gives a nicer effect personally (letting the shade of the lamp's model show up as a shadow on roof/walls).