It worked for us to an extent. DD was easier to settle (ie. less screamin at even the hint that it might be bed time) using some of the routines but still requires being rocked until completely asleep and still only cat-naps. That said, I wasn't particularly disciplined about sticking with every detail long term.

What it did do for me is provide the reassurance and resolve i needed to continue with gentle methods and not give in to those who were telling me to 'let her cry'.