This.

The problem with getting measured at a shop and then buying a bike online is the fact that not all frame sizes are made equal. Just look at the geometries of the two bikes you posted. Compare the same frame sizes, and you'll see that they have different geometries. A 56cm from one company is not the same as a 56cm from another.

You've got a sizable budget, a lot more than what I had for my first bike. Don't worry too much about getting something with amazing components. Go into your local bike shop, let them fit you, test ride some bikes, and then save some cash for equipment (shorts, jerseys, helmet, etc.).

Given that this is your first bike, you probably wont notice the difference between certain component levels, but you will notice if a bike doesn't fit you right.