I've flown LH TATL >10 times. For me the deal breaker is the lack of air vents on LH, coupled with a cabin temperature that is mandated at 26C, according to the CC I spoke to when I complained how hot it was onboard. For me it was pure misery, no air and hotter than hell...The rest in terms of hard and soft product? I'd probably give the nod to UA, but I'm into LT mileage building and that means flying on UA metal on a 016 ticket....