For a Novella, there isn't really enough to this story.
It is a brilliant bit of worldbuilding, especially the ideas behind how the stasis works and how they plan to keep Earth alive for so much longer against the natural lifespan of the galaxy. The time travel mechanism required by the narrative is an interesting and slightly different one and I enjoyed how Stross explored that. The "Brief Alternate History of the Solar System" segments were particularly good.
I do have a few problems with this novella, however. The second person narrative bits at the beginning of most chapters are pointless and annoying. I realize Stross wants to differentiate the possible alternate Pierces from "our" Pierce, but he doesn't really achieve this until the last few times, it remains annoying-as-hell even after we get it, and really how does making alternate versions of a third person narrative into second person make any sense anyway. Use a different font or something, I don't know.
Besides that, I was a bit annoyed by the invocation of Kafka, both as the appearance of the Internal Affairs guy and with a section called "The Trial" in which he appears. There wasn't enough actual reference to Kafka's "The Trial," or any other bit of his writing to justify this. There was bordering on 0 reference to Kafka besides Stross name-dropping him a few times. It annoys me when allusions are made to things like this for no good reason, and not really tied into the writing in any other way. If he wanted to have a guy look like Heinlein, I'd have loved it. Or if he wanted to really reference "The Trial" a lot in that section of this novella I'd have been okay with Kafka. But I don't like the randomness of what could have been a meaningful literary allusion. It seems like it just wants to name drop a bit in hopes of sounding more thoughtful.
Which is too bad, because the story is pretty thoughtful as it is. I love a good time travel story, and this one is intense, suspenseful, and has possibly the grandest scale and best sense of wonder I've ever experienced from a time travel story. But there isn't much more to it. Like I said, this piece oozes Heinlein.
So I'd recommend that anyone who enjoys time travel stories (or Heinlein) even a little bit should read this one. But I can't recommend it as an award nominee. 4 out of 5 paradoxes overwritten.