I just published the first three Sexton Chronicles: Sexton, Sexton Spice, and Storm Clouds Over Sexton as paperback books at Authors Den. Authors Den only charges for printing and that lets me charge a little less for the authors den versions of the books than Lulu. Now there are three places you can by my books: Authors Den, Lulu, and Amazon.
All things being equal, I'd rather you buy them from Lulu or Authors Den. Amazon charges the same price as Lulu, but I make significantly less from Amazon purchases and I get paid (the significantly less) three months after you make the purchase. It could be up to six months depending on when you buy from Amazon, but Lulu is kind enough to pay based on a promise from Amazon. (That only adds to the credibility of Lulu, in my humble opinion.)
I found the process of publishing real books on Authors Den to be a little clunky. I had to try several times to get the covers to look the way I want them to look. I got there eventually, but it wasn't easier. They're new to the game. I assume it will get better with time.
And I really like the covers. Take a look!