One aspect of a photobook is the image quality. Another is the feel of the paper (and hence the book as a whole). Another might be the durability of the binding.
It's hard to see samples. and a bit expensive to experiment.
It seems that the lay-flat books all use photo paper stuck back to back - so despite the images being hi-res, aren't the pages a bit cardboardy, like a book for the under fives? I haven't seen one, but I imagine that barring abuse or accidents, the page hingeing is fairly durable.
I've done traditional Blurb, and the printing is good but not true photo-quality in terms of resolution, whilst the binding is glued not stitched, and who knows how long it lasts? A nice product, though. I think that they use a better glue than a cheap paperback. Their mid-range papers are the best bet (circa 150 gsm). Whitewall seem to be pushing a similar product?
I feel that I want a book to feel like a book as you turn the pages - the degree of flex in the paper is a tactile expectation.
To have stitched signatures (and so proven longevity) needs a big print run, and the printing won't be photo-print anyway.
So it's not just about price, but about balancing out all these factors.