"I don't care about the grass fed part really"
The organic grass-fed part is the most important for health. grass-feed beef is actually healthful, with a more Omega3 that omega-6, -9.
cows evolved eating fresh, low-carb leaves (grasses), not seeds (corn, soy, etc). Feeding cows anything but grasses is a perversion.
Non-grass high-carb feed, along with anti-biotics and growth hormones, is used to fatten them up fastest with the smallest inputs. They don't know why, but anti-biotics makes the feed more bio-available, less waste. The carbs screw up the cows digestion, making it too acidic, which promote of the poisonous strain O157:H7 of E-coli.