I use 3d coat for retopology, to create usable figures with mid to low poly counts out of high-resolution Zbrush exports and voxel sculpts. I do this manually, “drawing” the new topology over the high-resolution models. It’s a comfortable process, but it takes time.  

 

It may be unconventional, but I prefer to sculpt at high resolution during the creative process and establish workable topology after the fact.

 

I’m too busy working on my own stuff to offer my assistance with benchmarking but I wish you luck in your quest for an adequate retopology toolset.

Download my free stuff here: http://www.renderosity.com/homepage.php?page=2&userid=323368