I cruised through most of it. But the last three chapters really twisted my brain (continuations, the Y combinator, and the metacircular interpreter). I was familiar with the concepts, but figuring out the programs by myself was a tough exercise (I haven't read SICP though).
Opening it on my phone, this paragraph on the available ebook formats very much made my day:
> A 386 can, in theory, run Linux, Emacs, and a Scheme interpreter simultaneously, but most 386s probably can’t also run both Netscape and the necessary X Window System without prematurely introducing budding young underfunded hackers to the concept of thrashing.
Trust me, it will :) The last few chapters on CPS and the Y combinator are roughly a vertical segment on an otherwise nearly horizontal learning curve.
I'm 1/3 of the way through The Little Schemer. So far, it's not taught me anything I didn't already grok from SICP. I hope it picks up!