I've carried two smartphones (and often a third) for years. But I'm addicted to multi-platforms when it comes to mobile communications & computing. Laptops and Smartphones are my constant tech companions. I have an assortment of business & casual cases/bags etc to carry them in so it's easy to bring the devices of choice for any particular day.
Although I'm into choices and variety, my primary choice of computers is, and has been MacBook Pros.
The iPhone is my primary smartphone of choice, with the Samsung Galaxy Series being a very close second. Apples iPhone is beginning to frustrate me for just one reason, it's tiny screen. If I didn't have these gorgeous large Android 4+" displays I wouldn't be so spoiled. Windows as implemented on my Lumia is not bad, yet I'm not that fond of it's Social Media Centric orientation.
If Apple goes with 4.3" or larger, i'll be extremely pleased. At 4.0" or less it's still incapable of returning a ratio of 16:9, which is ideal for videos. 4.3" produces a perfect 16:9 while the phone can be kept very compact.
At the end of the day, if Apple is going to remain current, they will give up being stubborn and increase the display size. It's no secret that they programmed the public to accept what they make, nor will I abandon the iPhone. I will simply demote it to a secondary phone within my selection of smartphones.