"If you can afford these high(er) end apps, what are you doing in a Poser Forum?"

Well I continue to use Poser for a number of reasons...

• It's fun :)
• It's nice to have a large library of content available
• As a prototype or pre-visualization tool it has a lot of advantages
• The Poser market is one worth keeping an eye on

"Do you have any links about that? I know that you can use ZBrush to create displacement maps, but I haven't seen any hint on the website that ZBrush actually is a micropolygon renderer."

The next Zbrush version is heavily focused on the displacement mapping system. There is a large thread on the topic at CGTalk with a lot of renders from the beta.