The advantage of the 12 is that it is
a 6 shot airweight. Mine is 12-1, and
it is a 2" RB and weighs 18oz.

I can carry in holster, and even in the
pocket on some clothing.
A 4" would not be to much heavier,
but it gives up some the carry advantages.

Mine is excellent shooting condition, and it would not
leave home for less than 500.... But, a 4"
would not tempt me too much.

Regards,
Old 112