Okay, so the rundown is as follows. For all the lavish, bright, interesting points of Mainspring, Jay Lake's novel falls flat for the most part. It's rushed in the good parts and padded everywhere else, the characters don't seem to matter other than as props, and the main character doesn't really show enough growth to make his journey make sense. It's a loud, empty mess that might be a good read if you take it slow and get it out from the library, but I cannot recommend in normal circumstances. It's got good worldbuilding, but that's not enough to save it.
More, as always, below.