I think its the lighter colored "grain" that most seem to have. I don't want to insult anyone with a different opinion but they just look cheap to me. Like those Chinese flea market knives that have the red and green laminate handles.
Some of the darker ones like the brown ones on MWTIC's BK 10 look better to me but still don't think I want them.
I would have to seriously dislike the performance of my Grivory to switch to mircarta.
I hope I have not offended any of the mircarta lovers out there.