My only complaint is that I was FO when this was rolled out in ATL and didn't get the email from Delta. Since they don't publish what the "elite" threshold is (GM/PM) I never knew id I qualified when I reached GM. Eventually I just paid for global entry rather than try to figure out the qualifications to have Delta submit my name.
Plus I don't know what happens if you reach that threshold after Pre-check is rolled out at your home airport. Eventually DL or the TSA will really need to define these criteria!