argh deleted my post :-/
ok once again…
thanks for the replies
@ragtag
sure the cgi in LOTR was build with a lot of manpower. i´m not so foolish to belive i can make gollum in a week 
the trollskin was only an example. just imagine the cloud renderer in photoshop for a displacement skin. or imagine a dried out desert ground with the cracks in in it. how can you make this with d-maps in A:M? or even worse some well defined creases or a mechanical surface (typo, geometric objects,…). the result has such a high polycount… in polyprograms you get more or less used to a rather dense mesh. you have the tools to handel them with relative ease.
the first time i used d-maps in A:M was when i tried the pumpkintutorial from www.dvgarage.com (sorry no direkt link to the tutorial. i downloaded the quicktime a while ago). the steps where so easy to understand. the displacement map was quick made. then i applied it on the basic geometry. hm… something wrong. higher mesh, higer mesh, once again higer mesh… this is ridiculous now i have a mesh so dense i can model it all by hand (even with all the bumps and knots).
some basic pictures are following:

@zandoria
quote from an other website:
"Displacement/Fractal maps dynamically subdivide the patches they are applied to, limited to 16 subdivisions per patch. For more detail, large patches may have to be constructed out of many smaller patches.
Work as designed …"
sounds variable to me.
i can remember that between some versions of A:M the way d-maps are calculated was changed. but i´m not totaly shure with it…