When you look at this video, when he switches between the normal scaling and the "detail preserving upscale" you can see, that all this new function does is it pretty much just blurs the image to get rid of pixelation and then it applies an unshrap-mask kind of edge enhancement to the blurred image.

It is also clearly visible in the sample from emanswfan - the edge enhancement is pretty horrible.

As to Spaced Ranger's link, for me the clear winner is the "SAR DataDependentLanczos" which seems to strike the best ballance between sharpness and unnatural edge smoothing (and apparently it's freeware) - some of the filters make the image look really sharp without applying edge enhancement but they turn the whole image into large sharp colored blotches, so it starts looking like a painting. I'd say the second best is VideoEnhancer, which preserves the most detail but has some pixelation and some mild edge enhancement.

Edit: Actually, looking at it again, the VideoEnhancer may actually be preferable in many cases, since it really does preserve a lot of detail - the SAR DataDependentLanczos would totally rock for upscaling animation though.

It would be interesting to see what AntcuFaalb's method would do with that image.

And another edit: Before, I only looked at the image from Panasonic4.avi and now I looked at some of the others and the SAR DataDependentLanczos actually seems to create some really weird artefacts, which would probably look really bad in motion, so the VideoEnhancer totally wins.