I think meehs is more or less spot on. These are both top rate bikes (and I'd love to have the option of choosing). From the financial perspective, I'd go with the giant to save a few bucks, but if i had the cash i'd take the tuscany.
But that's me. As always, when you have the option of choosing between high quality products like this, it's far more important to do a few test rides and decide which feels better for you. Don't be afraid to go on some extensive test rides -- if you're going to drop some bucks, the LBS will let you take a few nice rides. You're choosing between more than just Ti or C/f, but also compact vs. traditional. You're really going to want to work out what you like and probably try some other bikes that combine what you like and don't...