If you're going to get North Side, you might as well purchase South Side to complete the package. Publishers sure make money this way.
If I'd known of a scan site for the artbook, I wouldn't pick this up at all. What a great disappointment. Maybe it's me but everything here is boring. What you'll be getting are illustrations accompanied by boring hues printed on plain background. Of the 200+ colored pages in this book, there are only 10% that actually reached print quality. I can't believe the original price tag for the Japanese version of the artbook is 2500 yen. Unless you are planning to collect all of the CLAMP works, stay away from this.