The physical books: Knit. Sock. Love. weighs in at 1 lb 13 oz compared to Sock Innovation’s svelt 1 lb 1 oz. The extra weight comes from one extra inch of height, 32 more pages, and heavier paper.
The patterns: Sock Innovation contained 15 brand new patterns, all charted with one size. Knit. Sock. Love. has 19 patterns — 12 previously published and 7 brand new patterns, all charted, many with multiple sizes. The previously published patterns have been re-vamped, re-knitted in new yarns, re-photographed, tech edited, test knitted, and have additional sizes where possible. The patterns in Sock Innovation, with the exception of Kai-Mei, were what I consider column or grid-based, i.e. used a stitch pattern that was repeated around the sock in columns or in a grid. While some of the patterns in Knit. Sock. Love. are also column or grid-based, a larger number of them go off the grid.
Content: Sock Innovation is technique heavy whereas Knit. Sock. Love. is more of a coffee table book that assumes you already love knitting socks. Knit. Sock. Love. doesn’t explicitly teach you how to design a sock or other techniques, but if you study the diagrams and charts you’ll learn a lot about sock construction and how pieces can fit together.
The photography: Both books have clear photographs showing the socks from different angles, but Knit. Sock. Love. also has beautiful photography from Laura Kicey that is just… beautiful.