This is a novella that may have been only accessible digitally - I know I couldn't find a hard copy when I tried, but I had a few bucks in my Amazon account from deferring Prime shipping or something, so I picked up a copy on my Kindle for almost nothing.
Anyways, it's short but somehow takes its time getting going. The store moves along, but I got a good ways into the book and had to stop and ask myself "wait, so this is what it's about?". Once I got over that, I enjoyed it - but I guess my critique is that Stephenson is better at writing long books and maybe struggled with being terse enough to fit this story into the space that he had.
I give this a 3/5. It didn't really grip me, and the climax was over almost as soon as it began. Cool idea all the same, and I'm glad I read it.