Aside from 8.1.1 still being in beta, the issues with trying to judge battery life are that not all functions use the same amount of power.
I also have a 5s, and my typical battery life (usage) has been 5-6 hours. Updating from iOS 7 didn't change this pattern.
However, if I'm in Airplane Mode and just listening to music or going through reading list items, then I'll still have more than half of my battery life left even after 5 hours of use. Conversely, when playing a power hungry game, I'll be lucky to get 3 hours on a full charge.
EVERY iOS update has come with people complaining about the battery life. But, I suspect that a lot of this has to do with people simply using their devices more initially after updating. Unless people are doing identical things on their devices and timing everything, there's really no way to verify whether these observations about battery life are due to the actual increased power drain, or simply differences in how the device is being used from one charge to another.
Agree. Also remember that my complain is not with short battery life, but unreliable. That means, that under the same conditions, one day lasts 6 hours, and the next day 12 hours. How can that be? Was she doing something in the background during the first day, and finished, then the next day is less busy, thus consuming less battery? What can that be?