Not only are the MRC versions easier to clean, but I also find that they seem to stay cleaner. Well worth the extra money.
With the Monochrom, I suggest using the histogram function with the clipping indicators set at 1%. In shots with bright light the benefits of using say a 2X yellow will be clearly evident by how the clipping in both the highlights and in the shadows is vastly diminished or totally eliminated. A-B a brightly lite scene with and without a 2X yellow filter. IMHO the Monochrome with a 2X yellow hits the "sweet spot" of the Monochrome sensor.
My friend Steve one told me, "You cant print what's not there."
Cal