It is pretty impressive! Drawing like this needs a lot of skill. There are a couple of guys on my course who can draw nearly as good as this.
But it is not realy my taste either. Sure it is nice to look at and perfect in any way, but somehow.... tsss I don't know I guess I like the rawness of rough sketches were you still see lots of unused outlines. Also like the honesty of those. I always thought very finished pieces lack a bit of the dynamic a quick sketches have.