Quote - "I strongly recommend keeping your fingers from the GAIN slider, I yet only had bad experienced with it, newbs to Vue use radiosity gain to make the shadows lighter, you don't!! want to do that, instead use material based ambience or luminosity."

Well, than I am a newb. :-)
I use radiosity gain a lot. And Chippwalters is also a newb, according to your opinion, because in his InteriorPak he uses radiosity gain a lot. :-)

Radiosity gain can make a big difference in several contexts. For example, my image "old land of giant gods" has a gain of 3. That's the best way (and most realistic) to have those rich shadows in the skull.
http://www.renderosity.com/mod/gallery/index.php?image_id=1714990
I have many more images with gain.

There's nothing wrong with using radiosity gain, as long as you know how and where to use it, what cons it has and how to go round those. Material based ambience or luminosity are not a good replacement for radiosity gain, IMO.