Quite frankly, this series can't do me wrong at this point, so I may be a bit biased, but even considering that, I think this is very nice. It even has a short additional story describing exactly how Iriya ended up at the school pool on the night of the last day of the summer break.
On a slightly off topic, seeing as how these companies other than "MAG Garden" are producing memorable artbooks, I'm starting to think that "MAG Garden" is either clueless about making artbooks, or is made up of bunch of greedy executives and/or marketing types. I'm leaning towards the second choice because they add "PREMIUM" prefix to their artbook titles. Does that scream, "Marketing!" or what?
Thank goodness this wasn't released by them because I wasn't going to buy anything more from "MAG Garden" company after the AIR "Premium" artbooks.