I'm not wishing to get into a silly Samsung Versus iPhones argument, we all choose our phones for our own reasons, my Note 4 has been fantastic over the past two years, as have various friends iPhones.
However below is a good article for maintaining your Samsungs battery life, no doubt some sensible iPhone owner would be able to put forward a similar guide for extending it's battery life.
11 Tips to Boost Your Android Phone's Battery Life - Mobile Phone Reviews