I have two friends who used PA.
Amazon.com: Shine: Books: Charles J. Bishop,Michel S. Rogers
It is simply a vanity publisher... They have no marketing power whatsoever. My friends were very disappointed when they discovered what PA does. I won't call it a 'scam', per se... you can decide for yourself.
All PA does is to print your book for you with a Print-on-Demand structure. They do not ask for any of your $, so they are not as bad as some out there. But, they drastically overcharge for your book, knowing that your family/friends are going to buy it. So, they get a huge markup on the 25-30 or so books that your fam/friends will certainly buy to encourage you.
If you're going to bother with someone like that, you are better off doing a self-publishing deal... At least you'll make a tiny bit of $ for your trouble.