I only have Vol. 0. I'm ashamed.
Don't buy any more comics until you have read The Goon. Seriously, BLOWS Golly! out of the water (and I think that is a fabulous book). The Goon is a top ten all time title for me. It is AMAZING.
And what you really need to understand about 0 is that it isn't really scraps as much as it is really early work for him. Eventually he decided to create a storyline and his art is in a completely different place now than it was then.
I own like a total of 15 art prints, TWO of them are Goon prints by Powell.