It took me over 2 1/2 years to figure out what was up with magents; and, as I feared, the problem was rediculously elementary!

They really work well.    A "Modeler" is your other option, they can effect a mesh at the Polygonal Vertex, Line, or Surface.  Magnets only work on Lines, but I should think there is'nt much you can do with a Modeler program(like Carrara) that Magnets do'nt do.  Actually, a few minutes ago, I saw a python(by Cage) that promises Vertex Level manipulation for Poser!

Magnets are a lot safer than leaving Poser also.  I've heard a lot of horror stories about mesh's not being compatible after having been exported, and then reimported back into Poser, after manipulation in a modeler.

To get started with a Magent:

1.)  Make sure you have the Part of the Figure that you want to deform selected, when you clcik Object > Create Magnet.

2.)  The 3 parts to the new Magnet Set are now listed in the Props list for the Figure or Prop.

3.)  The newly created Magnet will have three parts; the Zone, the Magnet, and the Base.  Select the Zone.

4.)  Goto Display > Element Style > Wireframe!(That was the really hard part nobody told me about!)

5.)  Now open the Paramaters Palette.

6.)  Move the wirefram to intersect with the area you want to Deform.

7)  Select the Magnet part of the Magnet Set.

8)  As you alter the Parameters(Translate, Scale, Rotate) of the Magnet(Away from the Base)  the geometry within the Zone will be effected likewise.

BTW - Just rememebr the idea behind using magnets is not to create them with any morphs already on.  Nothing is stopping you, but when you want to turn them into their own morhs they say magents only really a face as it is unmorphed.