What sizes are the frames? My personal preference for a fixed-gear is a frame that's one size too small, easier to whip around. All things being equal, though, I'd pick the Trek. Having ridden a couple from different years, I found them very stable at any speed and real fast on climbs. You might find you're able to run a higher gear ratio. The short dropouts would be challenging to get the right chain length, but half-links are miracle workers.