2 Months with my iPhone 5S

This is mainly about battery life. I got my iPhone 5S mid February, and I am pretty happy with it. It is amazing and much better than my previous 4S. However, my battery life never seemed to be as long as what others had or what different websites claimed for the 5S to have after testing the battery life.

I get 3-4.5 hours of usage, and around 8-10 hours of standby from 100% to 20%. I'm sure this is not normal. I recently went to an Apple store and told them about this problem and they gave me a new iPhone. I was hoping for this one to be better, but it's the same, maybe worse.

And thank you but don't bother telling me about turning off certain setting or doing specific things to help battery life because I have done EVERYTHING. In fact, I'm now an expert on saving the most battery possible on the iPhone as I know all the tips and tricks after attempting to find a solution to my 5S's battery life problem.

I want to ask you, anyone with a 5S, what your experience with your iPhone 5S battery life is and what your normal usage/standby times are. I don't know what to do anymore but it seems as though there is nothing I can do...

Thanks for replies in advance.