This month's road bike action did a head to head comparison between these two bikes. It is worth checking out as it gives some pretty good insight. 2 out of the 3 experts picked the Trek. A bit more traditional in design. The future shock on the Spec is new and adds complexity to the bike. I would look at the Trek SL6 disc as it is spec'd a little nicer than the Roubaix. That being said I recently picked up a Roubaix Comp. The only knock on it is the Frankenbike approach on the components. Mostly ultegra, but has a 105 cassette, kmx chain, praxis cranks, and the mid level ice tech rotors where the trek is all ultegra. I had always planned on getting some s-works carbon cranks which the praxis chainrings will work on so no issue there, but I have already already upgraded the cassette, rotors and chain making the price difference negligable. Either bike will be great, buy the one that feels good to you.