Having the ability to handle both nurbs and polys in one modeling program is definitely an advantage. FormZ and Rhino come to mind as two applications that have had this ability for a very long time.

What I have been hoping for is some new surface description format that will effectively replace both. That would be a breakthrough, and would eliminate a lot of wasted time and/or redundant effort.

I know about T-Splines and PowerNurbs, but neither is quite there yet.