I've been testing the new Sparse Voxel Octree Total Illumination feature of the Cryengine. And it's amazing. It's fast, accurate, allow 2 bounces in real time and even voxel reflections. Here is a first quick test about a full time of day animation:
In this scene I use the integration mode 2, with specular. Cone max length 30, and diffuse cone width 8.