Breakthrough Photo X2 v. X3 ND filters?

[Brookie]

Has anyone compared (or seen compared) these two ND filter series from BT?  I'd like to know what the image quality (i.e., color shift and sharpness) differences are between the two. There have been some articles praising the X3 but I have seen zip on the more affordable X2.

My use will be for landscape work with a Nikon D750. I'm most interested in the ND3 and ND6 plus stacking the two together for ND9.

[BobDavid]

The coatings on the X3 series are more resistant to scratches, finger prints, and perhaps water. I like the X3s. The Breakthrough filters are slim, which is a plus for stacking on a wide angle lens. I like the Hoya Pro series too. They are much less expensive. The disadvantage is that they are not at all slim.

[brianrybolt]

Has anyone compared (or seen compared) these two ND filter series from BT?  I'd like to know what the image quality (i.e., color shift and sharpness) differences are between the two. There have been some articles praising the X3 but I have seen zip on the more affordable X2.

My use will be for landscape work with a Nikon D750. I'm most interested in the ND3 and ND6 plus stacking the two together for ND9.

I have both of these filters and am very satisfied.  They are streets ahead of B+W.  Stacking! No Problem.

Brian

[Brookie]

Thanks for the responses guys. The X2 series certainly appears to have better coating than the B+W single coated filters and similar coating to the B+W MRC coated filters.

Brian - do you notice any image quality difference between the X2 and X3 filters that you have?