Poser is quicker and easier to use than other 3D Apps (it's one main advantage), but as far as realistic posing goes, it's not as powerful as some like Maya and Character Studio/Biped for 3dsMax. Starting with the boning and skinning of the character, the features in Character Studio are infinitely more versitile and powerful. The bending is cleaner and more realistic in these high end apps than in Poser (even though you can fuss with Poser's clumsy joint editor, it doesn't help the poor skinning).

Poser has it's advantages in the fact that there are so many pre-made morphs and poses available for it's figures, but for most users of high end software, using ready-made anything is out of the question anyway.

As for animating, there's no comparison. I could illustrate to you for hours on why Poser does not hold up to the standards of those software apps you mentioned, but I'll spare you the drama. Basically, I'll just point out that 3dsMax has a true dynamics simulator built into it called Reactor that can calculate and animate true physical reactions for a biped's interaction with it's environment... such as a character being hit by a car or falling from a high building or being pushed to the ground. Plus there's things like fluid and hardbody/softbody simulation, as well as cloth, rope, hair and more available in Max that just can't be duplicated in Poser (although the CLOTH simulation in P5 is just as good as any I've seen.).

Not to mention render speeds for animation in these high end apps are 3x faster when using raytrace materials, and the lights available in these high end programs are far superior to the ones Poser uses at the moment.

I wouldn't have time to show all the differences between Poser and those high end apps (it's a long list), but to answer your question, Poser is easier to use, and for certain things like still images, it's a quicker solution. But as far as advantages in REALISM or posing? There are very few. Like I said, Poser's realistic advantage is ease-of-use.

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.