I know this isn't answering the thread, but it's close. I'm going from an iphone 6+ 128GB to a 6s 64GB so there is a size change at least. My wife and I got the 6 and the 6+ respectively back in Oct 2014. We both have had it for 17 months each. While my wife is happy with the 6, I wasn't happy overall with the size of the plus. Even for a bigger guy, I had problems carrying that around and having it in my pocket. It was jarring going there from an iphone 5 but I was willing to try it. Well, I should have gotten a 6 from the beginning. Plus, the 128GB was too much for what I needed, so I went to a 64GB even with the 4K video and photos I'm going to have. Just wanted to save some money if I wasn't going to use all the space on the phone. So for 2 days now, I have a 6s 64GB due to an early upgrade through Sprint and its fantastic. I put it in my pocket and it disappears. I hold it in one hand and I can move my thumb anywhere on the screen. I don't worry about dropping it.
I considered going for the SE but after much thought, I decided despite the price point offered, I didn't want to go back down to a 4 inch because that would be a little too small, for me at least. I'm happy to say I've found the perfect size in the 4.7inch. I should also make a note of how much faster this is compared to the 6+; the 2 GB of ram really does make a difference and its butter smooth its almost ridiculous. I've also decided just to stick with getting the "S" versions of each iphone when I do decide to upgrade in the future. Just my opinion.