As a security guard should I carry a S&W Model 10 revolver or a Glock 17 pistol?

We have our choice as long as we qualify with the weapon. The Glock can hold more rounds and can be reloaded faster. But the S&W model 10 is an old standby. The S&W model 10 in .38 special seems to be more accurate. Which would you choose? You can only carry one. We do not have the option of carrying a different gun other than these 2 so no answers like "I'd carry a 1911 in .45ACP". Our firm only lets us decide between these 2 firearms.