Is there any reason for not? Occasionally they release a new system version to fix problems with the prior ones. What's wrong with that? At least apple is more regular about it than android seems to be? That's why I love them. What do you on your phone you are afraid to lose ? If you are jail broken it voids the warranty just to let you know. I have this version and no errors.
If you are familiar with jailbreaking and have your iPhone jailbroken, DO NOT update to iOS 6.1.4 or you will lose the chance to jailbreak until iOS 7.
And why would you ask if it's worth it? Small updates like this usually fix bugs and if they caused any problems you would've noticed the uproar already.