poser isn't really a modelling program at all, though it has some miniscule ability to fiddle around with combining primitives.  trust me, you don't want to do that; it's clumsy beyond belief.

zbrush is ... different.  it lives in its own dimension.  absolutely fabulous for creating detail from what i've seen.  i don't know how fabulous it is at basic modelling -- most people who use zbrush appear to me to be developing their base mesh in another application.  but maybe they do that because they're more familiar with their other 3D program, and zbrush uses a very different approach.  it does appear to me to have plenty of modelling tools.

anyway, a quick look at the links below shows oodles of tutorials, including several for absolute newbies, and one for a dagger that makes me want to run out and buy zbrush right away!  looking at that dagger tute makes it seem quite easy to create jewelry in zbrush.

modelling consists mostly of matching of your mindset to your toolset, or the other way around if you can't easily shift to doing things in different ways (which is something that can be learned, with lots of practice).  if one modeller doesn't work for you (even though you started with the beginner tutorials, which is something a lot of people skip to their detriment -- learn to operate the controls before you start driving that automobile :), then you're best off looking for one that does things similar to the way you think about creating an object.

lists of tutorials:
http://www.3dcommune.com/3d/tut.mv?ZBrush
http://www.3dlinks.com/links.cfm?categoryid=13&subcategoryid=122