On level 24 of Tartarus at about 10 hours.
The artbook is ok, but as was mentioned, not worth the wait. It's only like 52 pages. Also doesn't help that while I think Soejima did a great job with the designs, he still doesn't come close to Kaneko. Was disappointed when I saw he wasn't going to be doing the designs this time around.
Also a bit disappointed in the soundtrack. They just stuck it in a paper sleeve in the artbook. No track listing, no proper case. They were so worried about the artbook, but let the soundtrack just stay in that piss poor condition.