Another vote for Artscow! I just got my first book from them, and it is beautiful. I also opted for the 8x8 size and really like it. It's very readable. The price is much less than 12x12, which is a big consideration because I have hundreds of pages to print. It's a comfortable size to sit and flip through. Takes up less storage space.
Also, Artscow's pages are stitched. Other sources are glued, which can come apart.