Vid 1:
- Lower contrast, more natural looking
- More jagged edges around objects
Vid 2:
- Higher contrast, lighter colors are too bright due to which shadows are less visible
- sharper edges, presumably rendered with higher settings
Both are the same file size and 4K rendered, I'd personally pick the first one.
sisiron1 is an upscaled version that maintains the original version as much as possible.
sisiron2 is an upscaled version that uses a function added in an update.
I don't fully understand how to do this, and it's difficult to explain, so I can't answer any questions about how to upscale.