I love both. But let's talk about functionality.
BW with screen tones fits better for print.
This happens in the Japanese manga industry.not in the American. This style works for large masses, cheap tint and paper for fast printing. Something like newspaper i think. Maybe if the comic gets popular, they'll start adding color pages special editions etc.
Now color. Color means lots of investment in the print side. But in the RGB world, is really welcomed.
So, if you are working digital, colors fits for you. People who read the comic from a mobile phone look for stunning graphics.
Now, some comics have a style with purpose (BW or 1 color) and also a great story. And still are popular. So I guess it depends how are you going to create the symbolism or meaning of your comic.