Quidam and MakeHuman have strengths, but their mission is a little different from Poser / D|S. Quidam and MakeHuman (hereafter referred to as Quidam 'cause I'm too lazy to type it out every time I mention it) is a figure creation program with no animation capability, rudimentary lighting and none of the whiz-bang material creation that Firefly can do.

Quidam allows you to take a base character and morph it. It's tools are "sculpter-like" with brushes and falloff zones. You can squash and stretch limbs. MakeHuman allows you to morph between gender, age and body types.

Quidam Pro allows you to export your meshes at very low resolution (around 4K polys), so that was a big plus for me because it makes rigging in my favorite non-Poser program a lot easier.

Quidam characters aren't as photogenic as the DAZ characters, but they can be great background characters or can be really stunning in the hands of a master morph person.

Quidam's documentation it pretty good. You could probably read it all in 90 minutes. MakeHuman's documentation was even slimmer, but last I checked, it's not even version one yet so that could change.

Oh yeah, you can set the navigation controls to mimic your preferred "big 3" programs, so it feels pretty natural from the start.

In the end I said "to heck with it all" and started modeling my own humanoids to cater to the strength of my renderer.