I have the old version, and I've read that the new version is better for folks who want to use the exact same yarn as was used for the pattern.
Nancy Bush accomplishes two major tasks in this book, and does them both very well.
1) Provides updated, modern takes on knitting patterns written in nineteenth-century Britian, in ways that are both very knittable and fun to wear.
2) Introduces the knitter to the structure of socks, and how heels, toes, stitch patterns, yarns and needles work together.
Both themes have been tackled by others, but not with quite the same style that Nancy brings to the table.
The second and third chapters are well worth the read, even if you don't want to knit the patterns. This very quick history of knitting, and these patterns' place in it, is fascinating.
Twenty patterns follow, ranging from easy to advanced, with sizing from baby booties to socks for a "gentleman." They are all well-written and look like fun knits.
Overall, either edition is worth every penny.