A small addition to cfischer's detailed message, stick to a program until you become *G. Then if you're not happy with that airline try a status match to see if another airline works better for you.

Flying from/to NCE LH and TK are your best options. Unfortunately, IST is increasing the travel time when traveling to the States.

Considering M&M's latest updates for status validity (just 1 year so you've to keep the same tempo of flying every other year) I'd go with M&S.