This is a subject with about as many answers to it as there are responders. It's a highly subjective one with many aspects to it. You should ideally ask yourself, what is it's primary purpose? What might be a secondary use? How will I carry it? And where?
In reference to these questions, one must make many compromises in regard to type (SA, revolver), power, weight, comfort, and cost.
I finally (at least for now
) have settled on an all steel S&W J-frame 3" 357 to be carried in a IWB holster for a right hander. I'm a lefty. But carried IWB in the small of my back, the grip is pointed to the left and works for me.
I can shoot 38 Specials, + P, and 357s as I desire.
This is not THE answer but it is ONE answer.
