Sorry as I'm unfamiliar with STEP's mod testing policies. I don't do thorough screenshot-based comparisons myself, so I don't have that kind of data to share with you. I just play through areas of the game, if I like it I keep it, if not I change mods. For me, Skyland AIO is more visual pleasing, and yet still vanilla like so I overwrite Skyrim Realistic Overhaul with Skyland AIO. There are nearly 1400 files that overwrite SRO, and nearly 600 files that SRO doesn't touch.
Edit: Skyland AIO can be installed from its FOMOD to only include meshes and textures (as I typically do). Installing plugins are optional.