I just bought my 2nd road bike...this week! For what it's worth:

I'm 5'1" and I do have the longer legs/short torso so I went with a WSD. It is the only that would work for me, but you may have more options. I started with an XS (44 cm) aluminum frame with carbon forks, but Sora/Tiagra components. I rode this bike for 1 1/2 years and about 6000 miles. I was not able to buy a nicer bike at the time, and over time I could tell the aluminum bike was not the smoothest riding. The bikes you're considering are a little nicer because of the components.

My new bike is a Specialized Ruby Comp, full carbon w/ 105 components- the ride is more comfortable, and the 105 is big improvement. I'm really happy with it (now that I've replaced the saddle with my old saddle).

I rode 3 bikes: a Trek madone, Cannondale Supersix and the Ruby.

Is price an issue? Can you afford a carbon frame? Or do you see this bike as a stepping stone to a nicer bike later? Can you find anyone with a small steel frame bike you can try?

Feel free to PM me as I just finished making some of these decisions