Well, I am hopping off the S6 wagon as soon as I get my 6+ tomorrow. Great device but not enough to deal with the biggest shortcoming: battery life. Another issue I had is with Samsung overall, their lack of timely updates hamper the user experience. Those two issues cannot make up for an amazing screen, good UI, top notch specs, etc.
I'm personally satisfied with the S6 battery life. Stand-by life is great, and I get about 5 hours of screen time when set on auto brightness. I will admit that the first week on battery didn't look promising, but it got much better. I'm on T-mobile 5.0.2.
I could understand if someone isn't satisfied with battery life, but timely updates when the phone just came out? How is that an issue?