I went over and checked it out this morning (library nerd that I am). I only did a quick tour (30-45 minutes) so I can't really speak with authority to the functionality of the space, but I will say this; it felt right. By that I mean you can orient yourself pretty easily. It's big, but you don't ever lose the sense of where you are, and it invites you to find your way around.
I loved a lot of the details too. There's some old schools stuff (bronze, oak, buckeye leaves, and block "O"s), but also some real contemporary touches (the polished steel language motif recurs a lot and is fun). There's also quite a few interesting material choices (glass steps, some kind wire mesh finish in the elevators, polished marble, etc.). The cafe looks nice, the conference rooms are a great idea, and the Grand Reading Room is gorgeous. It's definitely worth a visit.
I blogged about it on my blog and posted some pictures too:
Oh Shiny New Beacon of Learnedness