IMO the 12 is the most versitile and has the most loads for it
It can go easly from goose hunting to upland game to deer with slugs or buck shot to bunnies. With skeet ,trap and sporting clays to boot.
The other 2 lack good loads and payload capasity for goose , duck and other longer range shooting.
My guss is
The 12 has the 16 beat in loads avability 50-1
The 12 has the 20 beat in loads avabilty 3-1