Im and old costumer of iPhone 4s / 5s and i moved to Android phones. The difference in those phones is that iPhone is very limited in apps but it's very fast in it's iOS.
Bad in iPhone: Apple every 5/6 months are making a new iPhone. They updating the old iphones example 4 and 4s so the people to go at 5 and 5s. If you wait untill summer im pretty sure they will release iPhone 6.
Good in Android: Tons of apps and free. They are not so fast as iOS but if you search they got so good apps.