If you are actually paying for business class, there are three essential rules for international travel:
1. Never fly a US airline.
2. Never fly a US airline.
3. Never fly a US airline.
If you want to collect UA miles to gain status, one option is to fly a Star Alliance airline and credit miles to UA.
Here in Japan, I am lucky to be able to fly two world-class airlines: JAL and ANA. They are both worlds ahead of any US airline in every respect.