I'm guessing that when chefs go to the meat market early in the mornings to choose the best cuts of beef, they are doing it for a reason - what do they look for when judging raw beef that they will use for Steaks? 
A few things:   grain fed vs corn fed vs grass fed. Each style lends their own flavour to the beef.  free range vs. feedlot. Cows fattened on feedlots will have more fat; the meat of free-range cows has a deeper flavour. Feedlot cows will also be more tender. 'Organic' (a word with no meaning really) vs non. Some chefs are concerned with antibiotic and hormonal treatment of cows; generally speaking, something labeled 'organic' is less likely to have been chemically treated while alive. marbling, the degree of intramuscular fat. More marbling = more flavour. Bear in mind of course that some cuts (e.g. tenderloin) have very little intramuscular fat. aged or not, and wet vs. dry. Aging meat allows lactic acid to denature proteins and increase flavour. Dry aging is significantly better for this than wet. However, that comes at a cost, as dry-aged meats must be trimmed, resulting in a lower yield per initial pound of product.   