I am likely taking a trip to South Africa over the summer. I am considering flying business class in one direction from JFK and I was going to book the flight on United.com since they are partners with SAA and they give me the easy option of choosing which leg to book the business class on. They do not let me pick seats on United's website so I was wondering if there will be any issues with seat selection or availability? Or will I someone get a located on SAA's website where I can choose seats there?
Additionally, are there any other major differences I should be aware of?