Carry the gun that you are comfortable with and well practiced with. I'm a big revolver fan.
The .357 magnum has it's advantages and disadvantages. Over penetration, excessive flash/night blindness, heavy recoil are some of the more notable disadvantages. Consider using .38 Special +P SJHP or SWCHP (the "FBI load"). Over penetration potential of the .357 mag concerns me. If I can defend myself just as effectively with .38 +P, without risking having to explain in court, why I chose .357 mag. if my bullet goes through my target and injures an innocent.