The obvious ones are Lux and Octane. I've used Lux but not Octane. Lux takes a long time to render unless you have a compatible GPU, Octane requires a compatible GPU.

As you point out Vue will import Poser scenes although its normally necessary to tweek the shaders to get best results. I would say it does not have much an advantage over Poser for rendering figures realistically (others may disagree on that point).

What type of scenes are you looking to render?