Karen Russel is two or three lexical generation ahead of me. Neologisms like 'tankini' throw me for a loop, not because I can't back-engineer them and figure out what they mean but because they seem like words from a future generation of speakers to me, inhabiting as I do a word world where the Beats and Joyce still seem pretty radical. I'm often overwhelmed, and frankly unable to swallow some of her more sesquipedlian feats of language virtuosity when placed in the mouths of juvenile narrators.
Also, perhaps it's all a bit too modern American for me. Modern America is the least interesting country in the world, because the most ubiquitous and attention-demanding.