
Yes, I do.  A couple of years ago, I did a comparison of the two
products.  Some of this may have changed, but here goes.

As far as a PHIGS+ implementation, Figaro+ is fine.  But, its PHIGS!
Personally, I hate PHIGS because I find it is too low level.  I also
dislike structure editing, which I find impossible, but enough about
PHIGS.

I have found HOOPS to be a system that is full-featured and easy to
use.  They support all of their rendering methods in software when
there is no hardware support, their documentation is good, and they
are easily portable to other systems.

I would be happy to elaborate further if you have more specific
questions. 