Without a doubt, #2 is the best choice, Bike less than a year old, you can't go wrong with Ultegra.

EXCEPT - The SystemSix is Cannondale's fully integrated aero package. So ordinary maintenance such as replacing cables/housing can be a major PIA. If you do your own wrenching, are you willing to deal with it or pay someone else to? If you need a stem that's just a wee bit longer, that could be an expensive cash outlay for that integrated bar/stem. Need some more stack height on that bike? You could be SOL.

I still say it's the best option, but the true answer can't be found without riding each of the bikes and see how they fit you.