I've been playing with the recent v0.3.42, the one before they temporaily disabled MLT in v0.3.48 to add instancing support, and I'm impressed with the speed of convergence since the last time I played with it!
http://www.evermotion.org/files/noxRend ... 0.3.42.zip
http://www.evermotion.org/files/noxRend ... 0.3.42.exe
The overall image with Path Tracing and MLT cleans up way faster than Luxrender and even Indigo
caustics stay rough for longer than Indigo though.
Plus you can access all of the MLT settings individually!
Although the type of MLT seems different to Indigo, noise pattern looks different.
They have added the camera responce files like Indigo as well, but with a nifty option to preview of all the responces together on a single page with thumbnails - nice
And interestingly in the Post section, you can turn on/off direct lit and/or GI parts of the image, and even boost or reduce the GI
16 min render with MLT - 4GHZ CPU - pretty clean already, just the roughness in the refracted caustics