I am a BOS-based flyer though live part of the year in Marin County and the summer outside of Montreal. I'm been concentrating my point accumulation on BA (I'm Gold for Life) because I have taken the BA day flight to London for over a decade 4 to 15 times a year and more recently JetBlue because it is good for BOS-SFO and generally for flights to Florida and Charleston SC, etc. Because I fly all over, I am usually Star Alliance Gold but to get it, I need to credit my flights to Turkish Airlines (used to do this with Aegean and before that AC, thanks to the good advice of Flyertalkers). The primary virtues of Star Gold are: 1) access to lounges in Canada, the US and elsewhere without having to pay; 2) occasional upgrades to first on AC. I usually fly business class for work but will take flights to Calgary on AC and appreciate the upgrades.

In the past, I have not flown SkyTeam unless I had to go to ATL or occasionally Paris. However, Delta is ramping up in Boston and I am flying to BOS-ATL-SP-ATL-SP later this month on Delta and then to London later on Virgin (just came back from London on Virgin, though I will say I didn't love the Upper Class seats). Given AA's apparently self-destructive strategy, I can imagine that I might choose to shift significant business to SkyTeam. Is there an airline on SkyTeam that makes it easier to get useful elite status (e.g., gets in lounges, maybe upgrades) like I get on Star Alliance via Turkish?

I fly to London, Toronto, Calgary, NY, Sao Paulo and San Francisco regularly but also to Rome/Venice, Stockholm, Frankfurt, Tel Aviv, Mexico City, every once in a while and on occasion to almost everywhere (Sydney, Singapore,Vietnam, Croatia, Prague, Vienna, etc.). Usually business class for work but premium economy for vacations. In the past, I've avoided Air France and Alitalia.

Thanks for any advice.