Off-duty, I normally carry a Glock 23 (40) and sometimes a glock 27 or Walther PPK if I need more concealment.
Any pistol (revolver or semi) can potentially jam but if you keep your pistol clean, lubricated and loaded with factory ammo, your chances of jamming are very minimal. Anybody carrying a pistol for defense, should practice malfunction clearance procedures so they are prepared in case a pistol does jam.