My EDC is a Sig P228 in 9mm.
The first handgun I ever bought was a S&W J-Frame in .357 magnum.
All about the circumstances...I used to carry the J-Frame when it simply wasn't feasible to carry the 9mm.
Example: A few years back, we had a hurricane in my area. I worked private security at the time. My site was, of course, closed, but there were major concerns that the site could become a shelter if the storm became severe enough.
Even if it didn't, there were legitimate fears of looting. As a result, while on patrol, I had my J-Frame in my cargo pocket. I would not have been able to carry my Sig, much as I wanted to.