I looked at both before knowing which was which. Immediately I recognized the look of the top right photo, whereas the bottom right didn't quite seem to have "the look". So, I think it might be that it looks better to you because it looks more like how a photo looks. It's similar to how younger people may prefer 60fps or weird settings on TV shows that give it the "soap opera effect" vs how older people can't stand them.

After switching back and fourth and really looking closely at each one I ended up deciding that I liked the bottom right photo, even though I could recognize the top right one had a more classic film look. For me it was just because there was more detail in the colors. The original scan was kind of washed out in the blues I guess, as well as being a little more red in the dirt area.

I too preferred the top right photo. Arguably, it has less detail in the tree line, the city is neither better or worse, just different, but for me the skyline and sky are far superior with the top right photo.

Maybe this is prejudiced because this is how I remember old photos to be... But then, isn't that the point of scanning old negatives anyway - to recreate what the old images on them would have looked like at the time?

Arguably though, the correct solution is to preserve the source information as much as possible, so similar to what it proposed - scan the images using light sources that correspond to the peaks of the chemicals used in the negative, and then colour grade directly from that using a modified inverted curve.

Doing it that way should permit both outputs by changing the curves used in colour grading, and I suspect the real issue is just "inverting colours" isn't the most appealing visually, just as most professional photos are colour graded to some extent because the raw images don't look as appealing.

To me, the bottom right image has a smoother more gradual range of colors while the top right seems like the saturation is turned up a bit too high so many of the same colors blend in loosing some of those color details. Like the typical blue sky present in the top right, in the bottom right version goes from a similar vibrant blue to light purple as the sky extends to the horizon. Similarly the bottom right's foreground trees/hills details of green/tan colors pop out more more as they sit together giving you a greater sense of detail to the dense foliage.

The top photo has a blue-green cast, whereas the bottom photo has a magenta cast.

Maybe the bottom one is a more realistic reproduction of the scene, but I also prefer the top one, which is more saturated and closer to what I associate as a film image.

Each kind of film has its own character and color variations; it’s silly to try to neutralize everything.