They are both race bikes with race geometry. Both come with the same components, Shimano 105 (if that is what you are getting). The difference is frame material. Titanium has been used less often in race bikes than aluminum. There are a multitude of reasons but none-the-less aluminum is the material of choice for race bikes made of metal.
I suspect that the Specialized frame will be stiffer which is preferable in racing frames, so I would pick this one.