Like most things, if you don't start with quality ingredients, you can only take them so far, so yeah, sourcing of beans really matters. The skill of the roaster is critical to pull the flavors out of the bean that are desired (different roast profiles can accentuate different flavors.) Last, but not least, is the ability to blend beans together to produce a final product. This is a particularly critical skill as well, especially when you want to produce a "branded" blend that needs to be consistent from bag to bag. So, when I pick up a bag of Major Dickason, what I get in my cup is going to be what I expect.....not easy to do when you consider that the source product can vary (subtly, or less so) from harvest to harvest.
Of course, the price point and volume you are trying to hit affects all of these variables (and more) as well.
For my taste, Peet's is the most consistent producer of coffee I like. There are other, more expensive, roasters that I like as well, but 95% of my coffee gets roasted by me, so when I have the odd occasion that I run out, I usually just pick up some Major D.
R