I think you have to consider lounges and boarding procedures and onboard baggage allowances if your journey is not exactly point to point or if it crosses borders. All the airlines you list are good with First carryon baggage but vary in others. FOr example, the airlines could vary widely in location, availability and services at lounges. Their seats are not uniformly good on all routes (for example they have reconfigured seats on competitive routes, but have older seats on others). Their customer clearance and boarding support may vary too in non-US, non-European countries (i.e. they may have staff help with special customs and immigration lines).