All the bikes you mention are not inexpensive. Before purchasing, I would recommend going to your LBS and get a proper bike fitting. Don't spend a lot of money and get a bike you won't ride because it is sized wrong.
As for which, doesn't really matter, they are all fine bikes that can bring great satisfaction. Get what floats your boat. Any thought of one climbs better or is faster is utter nonsense.
Thank you - that's really helpful. Any benefit to the expensive fitting service some shops offer? Or is there little more to it than measurements and how you sit on a bike? Also, would the Supercorsa be ineligible for L'Eroica?