Up until recently, I've created and published limited-run books via iPhoto/Aperture with great success - high quality papers, printing and binding with turn around times of a short as 2 business days coming from the US to Canada (and with no extra charges for customs, duty, taxes and clearance charges). In fact, the two times I had problem with the printing of an Apple book, they shipped a new copy the next day - no charge, no questions asked, no need to return the damaged copy. That's customer service!
Being a LR user, I thought I should give Blurb books and go and have am just as satisfied with the quality of the book. In fact, Blurb's page layouts (via LR Book module) are in many ways more technically customizable (font characteristics, precise spacing, text boxes, etc.) than are the iPhoto/Aperture layouts. However, iPhoto/Aperture templates are far more artsy/scrapbook-like with partially rotated photos, different borders, etc. built into the templates.
In many ways, with iPhoto/Aperture you can produce a far more graphically interesting book with fewer graphical faux-pas as each style of template has certain features built in that can't be changed. As well, you cannot swap page styles between templates. Whereas with LR you can easily break all the graphics rules - great, if you know what you're doing, but you can just as easily produce a less graphically-dynamic (more boring) book or a dog's breakfast, if you don't know what you are doing (like some novices do when they are given PowerPoint, for e.g.)
The only thing you cannot do in either (at least to my limited knowledge) is freely rotate images on a page.
Blurb books cost more to ship and you cannot toggle off the Blurb logo on the last page without paying a hefty (~15%) premium. With Apple books you can turn off the Apple logo freely. But with Blurb, you can chose higher quality papers and you can market your creation to the world through their store and even have your book added to the iBookstore, but I have no experience in those areas.
Hope this helps.
