My parents refused to set foot in the USA*, so UA was always out of the question. As we know, the US is not a sensible place to make a transit, as you have to enter anyway.

Their RTW consisted of LX (LHR-ZRH-DXB),
SQ (DXB-SIN//SIN-KUL//KUL-SIN-PER
NZ (PER-AKL//AKL-SYD), and
AC (SYD-YVR//YVR-YYZ//YYZ-YUL//YUL-LHR)

Their ratings were SQ>LX>NZ>AC.

I suppose they ought to make a flight on BD to keep on the right side of the karmic forces.

* and I used to live near LAX!