Really enjoyed the first edition (it was the first thing that got Rails to 'stick' after years of not-really-getting-it and it's my go-to resource for friends w

Really enjoyed the first edition (it was the first thing that got Rails to 'stick' after years of not-really-getting-it and it's my go-to resource for friends who ask about learning Rails); how different is the second edition? Will probably end up buying it anyway but is it a complete rewrite or just some updates?