Well, I got my S6 in January and it's the best phone I've had, IMHO, since my S3. I had an S5 between them and that was awful. Battery life on mine is fine, I get between 1.5 to 2 days out of it, on average, but can always plug it into the car or external battery pack if I'm out and about so that's no longer a problem (I've picked up spare batteries for phones for the past few I've had, I don't expect them to last.)
Camera is excellent and I've had zero problems with cell reception at all.