A study of line- Opinion please?

Above is a sketch I did and scanned into Photoshop. Have I mentioned that I love blue col-erase pencils? Anyway, I'm hoping to ask some opinions on what people like best for line treatment here. I could tell you which one I'm leaning toward, but I want to know what appeals most to others. I could spend more time cleaning up all of these, but want initial feedback. Soon, I hope to experiment with different painting styles on this as well.

Thanks so much for taking time to comment!