Can't speak for anyone else but I always use Shaders on import and never have to adjust anything..!!
Also a lot of Poser props, characters are totally shader based, so if you have it turned off you get Vue's interpretation of a texture which is usually very poor.
Example: A skirt prop with Shaders and no actual image map, with shaders unticked it come sin with nothing on it at all, could be you want it that way, but if you want the look of the particular shader it's gonna be all wrong.
I like using the Shader option but I know there are others that don't..

Injustice will be avenged.
Cofiwch Dryweryn.