I just bought a CAAD8 Optimo1 about a month and a half ago. I loooooove it. I had been riding a Cannondale Killer V900 mountain bike rigged for the road, which I bought new in 1994.
I was not sure that I wanted another aluminum bike, because of the harshness of my old Killer V, but I am mighty glad I got the CAAD8. I have never seen anything quite like the CAAD8 Optimo1. It is fast, comfortable and handles as if it's on rails.
Moreover, I rode eighty miles yesterday morning, and I felt relatively fresh afterwards (and I am still recovering from a right femur broken last November). That never happened with bikes I had before. I should point out that the bike I had before the Killer V was a Trek 1000 aluminum road bike.
The CAAD8 is a beautiful, strong and responsive aluminum frame. Trust me!!!
I really think Cannondale hit the jackpot/sweetspot of the engineering of bike design with the CAAD8 frame.
I did test-ride the Synapse in aluminum and carbon, and while they were just okay, the CAAD8 spoke directly to my soul.
Find a Cannondale dealer close to you, test ride his road frames in your price range, and see what you think.
Remember, only you can tell if a bike carries on a conversation with your soul. When you find such a bike, buy it fast!
One important thing though, I swapped out my stock TruVativ Elita crank and bottom bracket for a Shimano Ultegra crank/bottom bracket before taking delivery of the bike.
Regards,