Some nice output here:
http://www.indigorenderer.com/category/image-galleries/best-indigo
very nice work there!
Personally i'm a fan of Luxrender.
http://www.luxrender.net/forum/gallery2.php
It integrates with Blender better than any other renderer, has some nice features and it's free. It could be faster though and in fact they are working on gpu rendering at the moment which they plan to release with the 0.8 build. They are taking the approach that instead of offloading everything to the gpu they are going to split it so some of the work remains on the cpu, which sounds like a nice idea to me.
2010 looks like it's going to be the year of GPU rendering, i'm seeing a lot of these sorts of renderers that either already support gpu rendering or have some kind of alpha gpu rending code like LexRender.
I have tried the Indigo Renderer with Blender. It does a good job. Never tried Lux, but I do use YafRay on occasion. YafRay can be tricky to use.
....and there is the new Octane renderer, another GPU based renderer.
http://www.refractivesoftware.com/index.html
I bought the Indigo Renderer just before the price went up and I love it :)
- Terje
I bought our favorite render, Terragen 2. Love it!
Yeah.... have that one too ;)
- Terje