Interesting. Will try another store then.
I'm fairly certain I know what my fit is, having done a fairly expensive triathlon fit and talking with the fitter about ideal road fit. The Vaya 52cm would require too many compromises since my reach is short. The Surly at 42cm would still be stretching the reach, but if the steerer is uncut (or short stem and risers, or maybe a moustache handlebar), then I could make it work. At this point, I'm more concerned about how each bike rides, how it feels, etc. And also the cost!
Thanks everyone so far for helping me out. Got phone calls to make!