The key to healthy AND tasty grass-finished beef, is HEALTHY SOILS. Genetics can play a role, yes, I agree. But the proper balance of the chemical, biological and physical properties of your soil will do FAR more. Anyone who knows anything about feeding cattle knows that, even in a feedlot scenario, the diet of the animal must be just so, to result in a desired product.
What makes any of you think for a minute that grass is any different? Just because your animals graze foliage does not mean the beef will be tasty. WHAT'S IN THE SOIL, IS WHAT'S FEEDING YOUR FOLIAGE, AND THAT IN TURN IS WHAT IS FEEDING YOUR LIVESTOCK. I am a firm believer in the necessity to balance our soils FIRST, focus on your grass second, and the livestock will fall into place.
There is a huge movement in New Zealand and Australia for grass-finished products, especially those from healthy, balanced soils. Anyone interested should check out:
http://www.cambrianmeats.com
Some very good reading on there. I've met Ewan Campbell that owns it, good fellow. Just another farmer who didn't want to follow along with the rest of the herd.