I just published a book with Blurb. One word, if you plan to print B&W: DON'T. I've had problems with books looking either green or magenta (hmm, seems like old Epson inkjet problems). To their credit, Blurb has tried to be very helpful and upfront in their efforts to rectify quality issues, but in my case (including a one-time reprint) it failed. I spend A LOT of money for a comparatively few books (to send as Xmas presents to friends, family, and more importantly, clients). I have an ISBN number, and everything else necessary to market and sell -- but won't.
My book, "Vanishing Ireland", I had planned on submitting to mainstream publishers. Originally, I thought I'd use Blurb to create a full-size, 10x13 mockup, but then thought, "What the heck. I'm going to all this effort, I might as well see about getting an ISBN number and selling it myself". Big mistake. I actually bought some other photograsphers books (color) that were 10x13, and the reproduction was actually quite good. But, mine sucked. It's 160-pages, 149-plates, and I used the B3 services, the 100# silk paper -- the works -- and it was still disappointing. Plus, the expense is high enough to be almost prohibitive. If I could be sure of quality, I'd go ahead and market the "First Edition" as a limited edition and could then sell it for what it should be priced for that. But, the sweet spot for fine art photography coffee table books is roughly $40-60. If I pursue doing it myself, I'll bite the bullet and do it properly, to the tune of $15-20K for 1000 copies -- but then the retail will be in line.
Basically, look at your reasons for doing a book. Are your printing color or B&W? Are you planning on printing a few dozen at most (or on demand), or are you looking to sell to a larger market? Finally, are you footing the bill? Based on these criteria, digital, on-demand, non-color controlled printing may be the way to go. In which case, Blurb may be your answer -- or many of the other similar printers out there. A last suggestion: pick up the latest copy of American PHOTO. It has a small article and listing of at least half a dozen small OD printers, along with the strengths and weaknesses. Good luck.