We both have AARP BCBS supplement. Before I went on Medicare, I asked my doctor's office which supplement was best from their point of view. It was AARP BCBS hands down. They said Humana was the worst. I talked with a friend who handled the insurance for my former employer. She is a bit older than I am and thoroughly researched supplements and recommended AARP BCBS. As RVers, one of our main concerns was portability across state lines.
I've been on Medicare for three years. A complete shoulder rebuild cost me $35 out of pocket. Didn't think I owed it, but it wasn't worth the time to fight it.