The choice lies mainly between android or iOS. With Android, you get a lot of free Apps on playstore; you might end up paying for them on iOS. As far as hardware is concerned, you cannot expand memory on any of Apple device. The flagship devices of both the brands are top notch. If you want simplicity, go for Apple, if you want to customize and would like to do more and more out of your smartphone, go for Samsung. Performance of smartphones from both brands is more or less at par, but overall camera quality of Apple iPhone is better. But Samsung's Dual-Pixel technology is not behind either. The battery life of Samsung phones is better than iPhone. Also, Samsung will cost you less too compared to iPhone. So, make a choice depending on what's your requirement - if it's ease of use only, buy an iPhone, or go for Samsung.