Being an owner of a Samsung Blackjack > iPhone > iPhone 3G > iPhone 3GS > iPhone 4 > iPhone 4S > Note 1 > Note 2 > Note 3 > iPhone 5S > iPhone 6 Plus
I can say there is a reason why I came back to an iPhone. Android is great, don't get me wrong. I loved tinkering with my phone and customizing it. I learned how to code some java and even made some ROMs and add-ons for my android phones which I shared with the wonderful XDA android community... However, in the end... iOS wins. Why? Reliability.
After so long you can't deal with the unreliable android OS. Sometimes you miss notifications, missed calls, missed texts, missed emails, rouge apps draining your battery, malicious apps that want to track your locations - use your camera - listen to your microphone, and the list goes on and on. It's things you can deal with because they don't happen often. But when they do happen you're SOL. After a few months I would have to erase my phone and start fresh just to keep that "new" feeling so the phone wouldn't get bogged down even though I run things bare minimum.
My Note 3 was the worst out of all of them. Not only were there major issues with the phone itself (people couldn't hear me when I made a call through the phone) but the software was buggy, and unfinished. 4 times my phone was sitting on my desk not being used and 4 times it came up with a crashed app process with no way to stop the error from coming up without erasing the phone in recovery mode. After this happening the 2nd time I tried going to an AT&T repair center to get my phone replaced. They took it in the back to check it and told me they had swapped it out. Turns out they gave me the same phone back, just cleaned it up and put the plastic back on it. By this point I was fed up and traded it for an iPhone 5s.
I'm not your average user, I consider myself an electronics nerd. For all that I do on my phone, every feature of that Galaxy series is a gimmick. The stylus was barely used in 3 generations of Note ownership. Never once did I use the multitasking. Fingerprint reader on the S5 is a joke. All that power, and the phone still lags scrolling through long menus.
Now reading this you may think I'm your typical android hating apple fanboy. In fact I hate apple computers. I think they're overpriced junk (I built a hackintosh for less than 1/4 of the price as the same spec apple computer)
At the end of the day, if you want a phone that just works, where you don't have to worry about removing 30+ Google and Samsung apps that you'll never use just to get the phone stable (Google movies, music, books, voice, games, and tons of other "bloatware") then an iPhone is that device. When someone calls me, my phone rings. When someone texts me, my phone receives it. When someone comments on my picture on facebook, the app actually works. (although with the way 8.0 is working at the moment this isn't 100% true lol) And now, with the 5.5 inch screen and a battery that can easily get me through the day I have no reason to look back to android.