Both of my publishers use it. According to one, it beats the hell out of LightningSource and lulu for quality, service, and price.
Still, if you are doing it on your own, we return to that just gets it set up and posted to Amazon.com (unless you buy the $39 package to get it at some other distribution points). This doesn't answer the more important issue of getting readers to find it and buy it. Neither writing nor producing a book are the most important chores--selling it is the most important chore.