If you simply want to see your words in print and purchase a few copies of your book for family and friends there's nothing wrong with using a vanity publisher like PA. I wouldn't recommend PA though; there are better print on demand vanity publishers around that don't pretend to be a proper publishing house and almost all of them are less expensive than PA. Lulu seems to get good reviews in that regard.
If however you have aspirations of becoming a recognised author vanity publishing isn't the way to go. If you want to be a real published author you need to be published by a real publisher. The publishing industry sees vanity published authors as third class citizens behind previously published writers and even un-published writers and will often reject any submissions from an author who has previously gone down the vanity-publishing road.
If you can't find a real publisher who's interested in taking on your work it's probably a good sign that it isn't marketable. If you think they are wrong, and J K Rawling is evidence that they do get things wrong, then the next best thing is self-publishing - that route isn't for the faint-hearted though. You carry all the print costs normally picked up by a publisher and have to undertake all the marketing yourself too. The upside is that if your book takes off you'll be beating publishers, and their offers of a lucrative contract, off with a stick - if it fails however you'll be several thousand pounds poorer.
It's horses for courses. If you simply want the gratification of holding a book with your name on it go for vanity publishing. If you want to be a published writer it should be the last option you consider.
Just my opinion.