I've found that, with Poser 5, there are a few glitches in the Materials room. Sometimes a material doesn't load. Sometimes it doesn't appear to load. Some of it may be related to a shortage of RAM.

But the materials library in the materials room is easy to use. It's just like using a MAT pose, but you work at the level of the material zone rather than the figure. The hard part is making your own shader tree.

There's some excellent free stuff out there. Check out what Mapps has done here.

And the picture -- the figure's camouflage is all done in the Material Room, with a quite simple shader tree. Though the detailed settings took a bit of time.