I use mainly La Femme. But more recently I've been tinkering with a new figure, Nova. Personally I can find uses for most of my Poser figures. I use Zbrush, Mudbox, Blender, and more recently have started to subscribing to 3d coat. For a strictly "I have an idea for a render and I need a human figure to look like..." It's really not an issue as all of these models can be posed, welded, and exported from Poser. Including clothing and hair. At that point they can be changed just as you would any basemesh or model. These things are obj models first and Poser figures after the fact, and this route goes in both directiions.

V4 has a ton of content. Plain and simple. I like her topology also, which I know is a contentious subject. Sasha 16 is ok. I don't particularly care for her weightmapping to be honest, it's better than nothing though. Both La Femme AND V4 Sasha 16 can be improved via further jcms to more fit my preferences, I've done so with La Femme (for, as yet, personal use, particularly for pin up/nudey mag type stuff). There's only so many hours in the day.

There's no perfect figure, in any software. Period. (Edit; a very subjective statement I know, the point being there's always fixes needed and room for improvement)