I have never used a Model 12 so I can't say.
For my hunting guns I use Model 37's. I have two, one is actually a Ducks Unlimited combo with a rifled slug barrel and a VR barrel with chokes. The Deerslayer is the best and for a goose gun they resist freezing up well.
I prefer an 870 for clay birds because I can see in the chamber and load directly into the chamber. I believe it is the greatest pump, just not my favorite.
At the moment though, I am lusting after a 16 gauge Model 97 for grouse.
For many reasons the 97 is easier to use than anything else I've shot on grouse.