I have the 6 and when I received it I was coming from the 5S and it felt huge to me at first nut now the 6 just feels anywhere from normal to slightly small. I just ordered the 6 plus so I'm hoping that I adjust to the size fairly quickly cause otherwise I might go back to the 6.
give yourself time to adjust to the 6plus's size. i had 6, then 6+, then 6 again then 6+ again. glad i gave myself the time to adjust and now i do love the plus. my daughter has the 6 and everytime i hold it, it feels so small. what more if i hold the 5S. so for me it's the 6 plus now.