To answer your first question last, they can be better, but not always. It depends on what you are doing with the clothing.  Conforming clothes are easier to work with for some poses as they follow the figure's pose, but skirts don't sit or kneel well.  The conforming clothing also doesn't lay as realisticly. It does cling better if you want a clingy or skin tight look.

The dynamic clothing doesn't need certain poses nor do poses come with it. You use the cloth room.

I've only been using dynamic clothing myself for a short time so I am no expert but here is a quick idea of what to do

1. load your figure
2. move the animation marker to frame 5
3. pose your figure
4. go back to frame 1
5. load your dynamic clothing
6. parent it to the figure (look under object menu)-this can be optional
7. make sure there isn't any skin poking through the clothing. repose or resize the figure if needed in fram 1
8. go to cloth room
9. click on new simulation
10. name the simulation and click ok
11. click on clothify
12. in pop up window select the chothing and click clothify
13. click on colide against
14. click add/remove
15. use check boxes to select anything the cloth might contact but you don't want it to pass through
16. click ok
17. click calculate simulation
18. take a quick nap...maybe
    if you reposition the figure you with need to recalculate

That's the basics. I'm sure someone will post links to a tutorial for more help

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