I already had *G with OZ, but due to the sale of the airline, I started looking elsewhere a couple years ago. Aegean and TK are the two most common recommendations other than OZ. IIRC, Aegean had some kind of requirement to fly on their own metal in order to most easily qualify/re-qualify. As there is zero chance of me doing that from LAX, I decided to go with TK. I was able to just barely get *G in the initial qualifying period and re-qualify in the first year after getting status. The downside is that TK M&S is a horrible program and my miles are practically worthless, especially after the recent devaluation. They also have some bad blood with LH,which makes earning on LH group flights a PITA.