I thought I would share my experience with you. My first iPhone was good for a few weeks until I noticed the battery cover was smaller than the metal housing and squeaked. It was a series 7 screen. So I sent it back for repair, since it was past the 14 days. Three days later the next one arrives. I feels different. Later I discovered it has a series 5 screen. The first thing I noticed was how washed out the colors were, a dead pixel, light bleeding at the bottom and a super squeaky batter cover.
So I called Apple again. Here comes the free loaner phone, until another iPhone can be sent. In my opinion series 7 has the most vibrant screen. Its also has better contrast than the 5. I think its unfair how Apple can sell a high quality and low quality iPhone's to us. If you really want to notice a difference, take the iPhone in the sunlight and see where the light sensor (detects your face on the iPhone when making a call) is. On series 7 its below the earpiece, on series 5 its above the earpiece.
