I also used Lulu to publish a book version of my webcomic strip
The God Interviews
I found Lulu useful in terms of the ease of uploading my PDF and of having the book in a 'shop-window' on their site. However, because my book is full colour throughout, Lulu's printing costs were too high for me to print the stock of copies I need to sell personally, send out for review etc. So I found another print-on-demand company, a UK one (printondemandworldwide.com) who print all the copies I need more cheaply, quickly and of excellent quality. I definitely prefer them to Lulu who, I think, overcharge for posting to customers. In terms of sales, I sold very few copies via Lulu and much more through my own website and at book fairs etc.

Self-publishing requires big effort, yes, and demands lots of time, promotion and planning. But print-on-demand doesn't have the old Vanity Press stigma now. Many mainstream publishers are using  this technology as being cost-effective and since the smaller independent publishers have been swallowed up by the big boys and since bookshops now charge publishers huge sums to display their books, the potential blockbuster is almost the only 'product' publishers are willing to consider. So it makes perfect sense for authors to use print on demand as an alternative, and the internet as a way to promote their work (as musicians and film makers are doing with YouTube and MySpace etc.).

By the way, I gave a talk on my experience of publishing via print on demand at the Apple Mac centre last year and again this year for the Hampstead Authors' Society. If anyone's interested, I've put the presentation on a video here

Blaugustine