I took this VND-diffusion filter with me on a work trip to San Diego and was overall pleased with its performance. In combination with the Canon RF 24-105 F4 lens, I got consistently sharp results when shooting both photo and video. That said, this filter does not avoid the typical issues VNDs face.

Sharpness:
This is the best attribute of the filter. Sharpness was not perceivably affected by the filter, even with a 45 megapixel sensor.

Color shift:
White balance does shift radically when changing the strength of the filter. I got the best results using AWB, which instantly corrected the shifting.

Cross-polarization:
The weakest attribute of this filter: cross-polarization is very present at certain strengths and fields of view. Anything wider than 35mm will be particularly prone to this issue. That said, this is a fairly typical issue with VNDs, and the effect in this filter is no worse or better than Tiffen or many other manufacturer’s VNDs.

Diffusion:
Diffusion strength is very subjective, but I find the implementation here to be quite pleasing and suitable for most uses. It’s visible, but the strength never dominates the image.

Mechanics:
The ring is metal and very solidly-built. I have no concerns of parts weakening over time. There’s a good amount of stiffness to the rotation, so I am never worried about accidentally adjusting it when moving around.

Overall, this is a great option for someone looking for a small VND-diffusion combo that is okay with the typical issues affecting VNDs. It does not replace my Polar Pro Basecamp filter, which has a usable range devoid of all cross-polarization and color shift issues, but I do tend to leave it on when running about or traveling. As long as you’re conscious of color shift and polarization quirks, you should be very satisfied with this filter!