As a LE firearms instructor I basically see 2 broad categories of folks using the smaller backup/off-duty guns.
The older shooters who came up using revolvers, and who are willing to dust off their DA revolver skills, often seem to do well with the little DAO J's.
The younger shooters who haven't done much (or any) revolver shooting, seem to gravitate to the diminutive pistols because they carry larger pistols as duty guns.
There are folks within each group who can shoot their choices well, and those who can't.
Being an older shooter, I tend to choose the J's (I have 7 of them, as well as a SP101
). I can shoot them pretty well.
I can also shoot the assorted little pistols well, but something about the little 5-shot wheelguns just seems to make them settle in my hand better while shooting them fast and accurately.
I also like the fact that the little J's are able to use heavier bullets than the .32's & .380's (although a 105gr .380 is nudging the lightest .38 loads of 110gr). There's been some decent development of defensive loads in the 130-135gr range for the venerable .38 Spl.
I try to avoid advocating for either choice when it comes to little handguns folks may be considering choosing for themselves. It's
their choice, since it's going to be
their lives (or that of their families) that are going to be on the line, after all.
I like to recommend they consider putting in some range time in assessing which choice might work better for them, especially when trying to use either choice in some of the more demanding courses-of-fire.