garysol1 

You are going to have a hard time finding a new roadbike at a shop in the $500 to $600 range. The cheapest road bike that we sell at my shop is around $800 to $900 and be made by Specialized. For the extra few hundred dollars you get a bike built by a professional bike mechanic with a full warranty.
In the sub $1,000 range you will find mostly Tiagra and Sora components. While I prefer 105 components or better the Sora stuff works fine when adjusted and installed correctly.