hi there madshi. first time I'm posting here but I'm using your VR for a long time now. I was playing around with the new implemented sharpen agorithms and so far I'm pretty satisfied with sharpen and crispen, both at default values. the effect with superres is too subtle though for my taste, but maybe my display resolution is too low for the filter to be useful. I usually watch 720p content with a native screen resolution of 1680x1050. regarding luma and adaptive sharpen, I also don't see much use for them. I can't imagine content where I would prefer them over the new four ones.
anyways, I wanted to draw some attention to a new developed downscaling algorithm by ETH Zurich which is called "Perceptually Downscaling" which gets pretty amazing results:
https://graphics.ethz.ch/~cengizo/imageDownscaling.htm
I think that could be a gread addition to madvr. according to the paper the performance of is pretty good (they implemented it with matlab) and it should be possible to execute it in realtime. it seems that they didn't publish the code though but the algorithm is explained in the paper and presented in pseudo code, it only consists of convolutions and sums.