OK, for me and both of my S6 edge and recently acquired Blue Topaz S6 battery life is very good, so no issues for me, but just to let you know, I just ordered an Unlocked S6 active and is supposed to arrived on Thursday.
So for those of you who love most of the S6 but think that it has a mediocre battery life, take a look at the S6 active, same great camera and display, same features plus Water, dust and shock resistant on a 3500 mAh battery that has been proven to be the best out there, even over the IPhone 6+ according to some reviews and tests, don't remember the article but according to the test, regular S6 had some 7 hours of SoT with that test and the active lasted 12.5 hours, while it keeps the wireless and fast charging options.
If you don't mind the looks, it's basically the best Android device out there, in pictures I thought it was too bulky for me, but after seeing it in person and comparing it side by side by side with my S6, I realized that it's like a S6 with an Armor or a thin Otterbox case on it. I ordered one the same day.