The Synapse or Ruby. The Amira won't be too comfortable for endurance as it has more racing geometry.
My Synapse has a fairly steep seat-tube. Wish I'd considered the Ruby (which is a little better for longer legs, I'm thinking, since it has a more slack seat-tube). How are you proportionatly? Long legs relative to height? Shorter? About equal?
Makes a difference too. The main thing though, is to try many different bikes before buying, and also find good local shops that let you test, and advise you on fit rather than try to push you into buying whatever stock they have on the floor. (I question the shop that appears to think an Amira is a good idea?
Unless the fit is so perfect that it is actually more comfortable for you. That's getting into something a fitter on here should speculate about, rather than me).
Also perhaps look into Jamis. I like the Quest. That is steel (much better, IMO, especially for the uses you mentioned. Want comfortable, smooth, fast?), but they also have fine carbon bikes available. Looks like the Xenith Endura Femme might be the equivalent of the ones already mentioned.
http://www.jamisbikes.com/usa/index.html