This is just my opinion and I am here to share with you my thoughts. Firstly it's the hardware, the nexus 4 lacks lte and the memory is capped at 16Gb with no expandable storage and 1Gb of ram. As you know android has a lot of customizable features it takes up most of the ram and most of the time I found it lagging. While the iphone knows how to take full advantage of what it has. I know there is a lte version galaxy s3 with 2Gb of ram but I have never liked amoled displays as the colors are not natural(I know everybody has their own preferences). I think I like both android and iOS equally but it is the hardware that separates them. I particularly don't like htc sense if you are asking about htc. I might be getting the galaxy s4 or the next nexus phone if they have more ram or storage capacity.