I don't own either, so I can't be too specific. I do think (IMO) that Cannondales are VERY harsh riding bikes that are much better for racing than street use. The CADD4 Cannondale that I raced on in 98 was a very fast BUT harsh bike. I wouldn't use it for street use on a bet, that's just me. I can only assume that since you're in the SS/FG forum and not track that this will be a street bike. I could go into how steel is a better choice for street/ city bikes due to ride quality BUT you told me not to do that in your post. If your going to ask for advice you have to be willing to hear ALL the pros and cons, not just what you want to hear.

So, buy the Cannondale. In a month potholes and rough roads will be on the list of things you don't like... along with sfcrossrider.