Here I cant say which one is better iphone or samsung because they both perform very well in all condition.
I want to review about iphone 6 and samsung galaxy s6.
I have used both this phone iphone 6 and samsung galaxy s6, here I well say that iphone 6 is much better and perform better then samsung galaxy s6 because iphone 6 had a better camera with perfect design and iphone 6 perform better music sound quality then samsung galaxy s6, im not saying that samsung galaxy s6 is not good but iphone is much better then samsung.
But one thing I like samsung phone is about display, for display I well go for samsung.