I thought this Red Box Games barbarian would make a good example of how the surface area of something metal influences what you can do in terms of effects.
A few of the weapons on this set of figures have broad, flat surfaces, which are prefect for adding in a little more depth in color choice.
In this instance, I was able to incorporate a more broad range of reflected color in the browns and tans. This would stand out nicely against the brighter, much cooler reflections of the snow colors.
The view in the center shows a little reflection of the sky, which now gives it a decent look from above. I know that there are folks who say that NMM is just a "one view" effect, but I strongly believe that the thousands of images on my blog would suggest otherwize.
Obviously perfect realism is never going to be achieved, but at a little over 1 inch tall, I say it does the job :-) I am not against metallics at all... in fact I like to use them myself. But this older article should get across the point of why I do NMM: