As of this writing, there seems to be much changes in the External Renderer scene for Blender 3D.
As you know Blender 2.49a has been released. Guess what. The official version of Yafaray does not work with this version of Blender! This is because, Blender 2.49a utilises Python 2.6, while Yafaray insists on requiring Python 2.5.4. This is such a pity, as Yafaray can produce high-quality GI-enabled images fast. I hope this situation get fixed soon.
Also, you will notice that Yafray (not Yafaray) is no longer listed as an option in Blender’s Render Panel. The old Yafray integration in Blender has been completely removed. This comes as no surprise as the old Yafray has been superseded by superior and more capable rendering systems.
Indigo has gone commercial. Kerkythea developers are working towards a commercial rendering system as well, although the basic Kerkythea will still remain free.
So, we are now left basically with Luxrender. And thank goodness, it is very impressive !
In my opinion, the most promising free external rendering system for Blender is Luxrender. The rendering outputs are superb and photo-real. You can even adjust the rendering result in real time. The exporter’s interface in Blender is good and reminds me of the great commercial Unbiased renderer Maxwell Render. Luxrender now offers both unbiased and biased rendering modes. So, now, you can choose between perfection and speed.
And, also not forgetting that Blender’s own internal renderer is getting better and better with each new release. Blender’s internal rendering and material creation system already support stuffs such as HDRI, Node compositing, Material nodes, sub-surface scattering, blurry reflection and Ambient Occlusion. With stuffs like that, Blender’s internal rendering system is really quite capable in its own right. The only thing missing is true Global Illumination, which is a niche currently filled in by the external rendering systems as mentioned above.