The one on the left is the results of a great tutorial, and here is my version.
The difference between the two is that a vector image is drawn using mathematical equations and not pixels. So if I made an image using vector graphics at the size of 4"x4" I could blow that image up to 400"x400" or 4,000"x4,000" without any change in the image--it would look exactly the same! If I make an image in Photoshop at 72 ppi (pixels per inch) at a size of 4"x4" and blow that up to just two or three times that size I would begin to see pixels, and the image would become abstracted.
So a vexel image is not a great image to make if you are printing it large scale, and Adobe Illustrator or some other vector based program should be used. But we are just emulating a vector image to create something , so we are fine.
You must conceive of, design, and then create a vexel portrait with an attitude--it must be dynamic.