Haven't been to the Ikebukuro branch yet, I'm saving that for a visit to the Nekobukuro, since we (the royal we, of course) don't want to make much ado of the fact that we're going to Ikebukuro, the Tijuana of Tokyo, willingly.

I have been, though, to the branch at the MO. I thought it was interesting, but gimmicky and unsatisfying enough that once is enough.