The new iphone 6 will only have a 4.7 inch screen. They were planning on making a 5.5 inch version but had technical issues with it and therefore will only be releasing a 4.7 inch version.
Considering the recent trend, 4 inch is a pretty descent one since you can comfortably put it inside your pant pockets.Normally people hold the 5 inch mobiles in their hands due to its size variation.
