Quite hard if not impossible to rank.

I would rate LH quite highly though, Star Gold get:
*First class check-in (separate from business class)
*Access to Senator lounges, which are normally quite nice (a few exceptions)
*Automatic seat blocking in economy (very appreciated, and it works!)
*Fast track at MUC and FRA (in MUC also separate passport control on departure to non-Schengen destinations)

These benefits tend to be quite consistent from my experience.