Wazzles said:

To me it looks like it has some standard up-scaling artifacts the way you do it. The superres one looks softer but cleaner, and generally more appealing.

Indeed, I used one of the most simple upscaling filter, but have you noted the problems on the superresolution version? OK, I must admit they are very tiny - infact you have to zoom in a lot to see them - but they are there... look in particular the eyes...

I expected much more quality, according to comparison examples...