We had a similar discussion awhile back. My feelings then as are now that B&W is far more demanding for me, as I have to make decisions as to where I want a tone to fall, what amount of detail to strive for in a shadow area etc.
With color I have little control of my final work, The color is there, if the film has the capability of "seeing" what you want to capture, you got it!. Studio color is much closer to B&W in the amount of planning that can be involved.
CC filters can drive you to the nearest bar. Artists/editors demanding exact color in a transparancy can make you glad you drove to the bar. Color photography came very easy to me, however viewing a full color scene on a bright sunny day can be a challenge for not only me, but a lot of others that know exactly how they want a "color" scene to appear when converted to gray scale. As I say, for me the outdoor color is simply see what you want to photograph, set up, ( which includes exactly the same steps necessary for a B&W set up) and make the exposure. I have never thought any part of the picture making process particularly "hard" but I do believe successful full scale B&W takes a bit more planning.
I think they are both harder. :)