Just few statements, unfortunately:
- commercial coffee are everywhere
- robusta added to many blends which make them to heavy and too invigorating for organism
- commercial coffee often comes roasted, while after roasting, it should be consumed within a limited time (e.g. 'Italian coffee')
So the things are better, when:
- coffee roasted in country of consuming
- coffee is ground right before cooking
- pure Arabica
P.S. When you get good coffee, sugar isn't needed, because it have taste instead of just be bitter. Single Origin very good for pour over, chemex or kalita.