Sorry, I meant this as an answer to Robert, but was also answering Chai. I got confused there..
Well, I like getting any ground meat I buy from a butcher I trust, re contamination and their general sources. That's true for any meat, but especially ground beef. I didn't know the business about not freezing the meat, as Roger mention re Spinn's restaurant, but that makes some sense re protein breakdown. I prefer Harris Ranch (California) beef , but that's out of my league re price. They have it at our local Sunflower Market.
I'm pretty saturated fat avoidant, but I like it in my burgers.
I agree with you on high heat/pink in the middle.