You probably did right on the sizing. Most cross bikes have a high BB making for a potentially alarming top tube height. I'd stick with a horizontal top tube to shoulder it for long runs.
STI will actuate canti brakes just fine, but not V-brakes. The side pull brakes _can_ work for cross, but they'll fill with mud and you'll have to let the air out of the tires to get the wheels on.
I'm sure all those bikes are just great at their price point.
Ron