I've used PNG files in AfterEffects for years with good results.  Open to any and all suggestions to improving my workflow.  One thing I noticed is that the "Alpha" PNG generated by Vue are not Alpha channels at all and don't work in AfterEffects.  Poser generates PNG with built in Alpha.

 

I was trying to do an animated asteroid in Vue, but ended up getting weird red artifacts along the edge of the asteroid and a supposedly Alpha PNG output that contained no alpha at all.  I gave up and imported an OBJ asteroid into Poser, textured it and animated it in less than an hour.  It came out terrific.  The Vue animation also had a really bad flicker that made it unusable.  Vue 8, by the way.

I love using Vue for set extensions and matte shots, but my experience with animation and Alpha channels has been dismal.