Mark Seiden, one of America's foremost criminal defense attorneys, especially regarding the use of deadly force, carries a SIG P239 SA/DA. He says that it's tough to defend clients who used a pistol like a 1911 .45 auto. That's why he carries the SIG.
Of course, what I just said won't have the slightest effect on those who are determined to believe that the type of gun or ammo you use doesn't matter in court. If you live in Florida, and you're unjustly accused, don't hesitate to call Mark Seiden or Roy Black. They may still defend you and your handloaded ammo, single action pistol and all. Of course, they are busy and don't come cheap.
I'm always amused at those who "have looked up cases and never found a conviction" because a defendant used this or that. The truth is that the evidence is like weight on a scale. It all adds up. When the jury comes in, the ammo or gun will just be one of the things that influenced their decision. It may weigh huge or very little.
A good attorney can debunk some of the false allegations, for $150 an hour, and you can always say "See there, no conviction because of the ammo or gun I used." And if you are convicted you can always say, "see there, nothing in the record says I'm in prison (or lost my life savings) because I used a SA, along with my own handloads."
You may never know if the jury's decision against you was razor thin and if your "killer ammo", or "gunfighter's pistol" is what made the difference--criminal or civil court.
Having said that, I have to agree the SA vs. DA issue, along with some others, may be more important in some places than others.