A number of members have made or are considering having made photo books using Blurb, because it is built in to Lightroom. Recently, member Lou received a book and he was unhappy with the results. When he contacted Blurb, they were, in my opinion, rather snarky in their response, and I felt that they were making the poor quality of the result his fault.
I looked closely into the Blurb functionality in Lightroom and while it is nice that it is built in, none of the guidance provided was highlighted or even indicated in the Blurb plugin. Perhaps Adobe should remove the Blurb plugin completely and simply direct people to use Blurb's own book building software. Not that doing so would have helped because the only way to know about these tips is to wade through their FAQ. I consider this lazy on their part, and I find blaming the client for not reading every scrap of dreck on their site to be very crappy customer focus.
However, should you wish to make books using Blurb, you really MUST read these articles.
Please note that soft proofing for Blurb only works in Lightroom 6 / CC according to Blurb so if you don't have either and want to soft proof so as not to get a product that makes you unhappy you will need to soft proof in Photoshop. This certainly puts the boots to the concept of simplicity and ease of use.