Does the 30 Day Shred Really Work?

I'm going to try this Jillian Michaels DVD workout this year through the holidays. I'm hoping it will keep the holiday weight off and take away a little bit of what I've been carrying around. I've done it before but I didn't get results that were anything like the befores and afters that I see online. Has anyone else done the 30 day shred and did it work for you?