I have 11 Blurb books and 4 Adorama (Printique) books. Of the 11 Blurb books, 3 had to be re-done because they shipped with "garbage" colors. The 3 contained a few images from previous "OK" books, so it was easy to see and prove. Blurb re-printed with no argument.
The Blurb books are OK and fine for the untrained eye - if the images don't push any color gamuts. But if you have images with bright, strong colors way outside the CMYK gamut, Blurb will disappoint.
The Adorama/Printique books are beautiful. The main difference, of course, is price. You have to sit back and wait patiently for a sale at Adorama/Printique. Sign up and enable receiving e-mails so you get notice of sales. 10% minimum discount, sometimes up to 30%.
If I need multiple copies of a book of snapshots of kids and relatives at family events, I'd use Blurb. But if I'm making a book of my fine art landscapes, street art, still life, etc., I'd use Adorama/Printique.