Rich, what is it that you don't like in the Poser renderer? What do you expect from your new render engine? If you specify your needs, it'll be easier to find a new renderer for you. They all have different strengths and weaknesses, e.g. C4D is a lightning fast raytracer but is really bad at depth of field or displacements; Maya has really good motion blur, I'm told, and I keep hearing good things about Lightwave's HDRI implementation. And if you already own Maya - why not go for Body Studio? You do already have a good renderer in Maya, and with Body Studio, importing PZ3s should be a lot less hassle than with other applications.