I see the trends before everyone else does usually. When the 3GS came after the 3G, I guessed the 4S would come after the 4. When the industry got confused when the next iphone was called a 5, I knew the follow up would be a 5S and then a 6.
I saw how the 4 upgraded the screen from the 3GS with retina display, and the 5 upgraded the screen from the 4S with a larger screen. Again, the 6 upgraded the screen from the 5S.
The S editions mostly add convenience. The 4S added Siri, the 5S added Touch ID. I think the 6S will again be similar, probably something akin to NFC easy payments or something we didn't know we wanted or needed until Apple showed it to us.
For the most part I'm happy with what my phone is and does. I'm still on the iP5, no reason I see to upgrade yet.
I saw how the 4 upgraded the screen from the 3GS with retina display, and the 5 upgraded the screen from the 4S with a larger screen. Again, the 6 upgraded the screen from the 5S.
The S editions mostly add convenience. The 4S added Siri, the 5S added Touch ID. I think the 6S will again be similar, probably something akin to NFC easy payments or something we didn't know we wanted or needed until Apple showed it to us.
For the most part I'm happy with what my phone is and does. I'm still on the iP5, no reason I see to upgrade yet.