Generally I believe in C OS is considered best (best food and service, at least pre-pandemic), with LX almost as good, and LH a fair bit behind (no direct aisle access for many seats). On the other hand I believe LH F is easiest to access via miles (if they have F on that route, obviously), LX has slightly less award availability and only on short notice, and OS obviously doesn't have a first class. This is also consistent with my own experience, although I've only flown any of these a couple of times, and transatlantic only, never to/from Asia.