Miguel links to an excellent article about what kinds of things influence juries. The conclusion is that the weapon you use does make an impression on a jury. It should be, but we share this planet with a lot of other highly irrational people. I agree with Miguel’s conclusion this means we need to get more women into shooting. Another conclusion to draw from this is to let your wife do the shooting. Women are treated less harshly by jurors in self-defense shootings. This effect also seems to apply to police shootings as well. Strangely enough, women are treated more harshly for using a Glock than other weapons.
Personally, I wouldn’t worry too much about this in terms of weapon choice. We shouldn’t let our irrational fellow citizens make our choices for us.