RandomControl has released Arion v2.5, the hybrid CPU-GPU render engine.
New render passes (AOVs), LightMixer layers, multi-layered EXR output, Metropolis sampling, CUDA 5.0, faster rendering. You can now control the number of GI bounces in a scene. Cropping the maximum number of GI bounces in a scene allows for a significant speed increase in exchange for a controlled darkening of the GI in hard-to-reach areas.
This feature is said to not break the unbiased look of an image. You can crank up the bounces as much as you like now, depending on the hardware you have at your disposal. The render component also features an exit color, extra control for SSS as well as a new Sampling system for image-based lighting. Also, the full time renderer, the new Metropolis Light Transport can run on a GPU. New effort has been put into Arion physical sun/sky.
Plenty more on the related links below.