I love Lethem, he's as good as any writer working today, but this one is a challenge. There is no plot. You're at least 100 pages in before there are any defined characters, and none of the characters are ever given actual names. it jumps around in time every few pages though, since there is no plot, that matters less than it might.
If I hadn't read Lethem, especially Fortress of Solitude, this one would have been more difficult. That said, if you like Lethem, this one is worth it.
Also read Up Jumps the Devil, a biography of Robert Johnson, the great blues musician. Of interest only to fans of Delta blues.