Natron is essentially a clone of Nuke, the ~standard compositing software for the VFX industry. It's impressive that it exists and competes with some very expensive alternatives.
Its maths and colour science is good and it seems to operate correctly on images. Unfortunately usability and performance are pretty weak. I've managed to replace Nuke or Resolve with it for the parts of my workflow that are colour conversions from e.g. ACEScg to sRGB, or for encoding videos (it wraps ffmpeg), but I'd hesitate to use it for anything creative and it definitely doesn't approach the animation facilities of After Effects.
Its maths and colour science is good and it seems to operate correctly on images. Unfortunately usability and performance are pretty weak. I've managed to replace Nuke or Resolve with it for the parts of my workflow that are colour conversions from e.g. ACEScg to sRGB, or for encoding videos (it wraps ffmpeg), but I'd hesitate to use it for anything creative and it definitely doesn't approach the animation facilities of After Effects.