IMO the only acceptable airside bus is no bus at all. Jetways were invented for a reason and any airport that does not have jetways is not acceptable, let alone excellent by definition.

If a carrier must use buses, they they should follow the lead of Aegean and guarantee that there will be a separate bus for business class passengers. Or follow LH and provide Mercedes vehicles to the stand for a group of passenges which includes me! AF does offer this systemfor IFC connections at CDG, at least for their won elites. Even CZ uses a small and relatively pleasant minibus from the lounge at some mainland Chinese airports. Having everyone tightly packed into a single hot stuffy smelly bus and then having everyone race and push for the stairs and struggling to hold their carryon while no one on the wobbly stairs moves is not a travel experience that I will willingly endure.