As a Star Alliance person, it's almost always Frankfurt. LH Senator made it a whole lot better, too. AF had a cool "Petroleum Club" program, too, which let an

As a Star Alliance person, it's almost always Frankfurt. LH Senator made it a whole lot better, too. AF had a cool "Petroleum Club" program, too, which let anyone marginally affiliated with the oil industry get free lounge access and other benefits. I'd still almost always prefer making my connection within the US and flying nonstop from the US to my final European destination. I generally only fly ex-SFO, JFK, IAD so there's generally a non-stop flight anyway.