When I first got my iPod touch 2G (2009) I was 14 but already very appreciative of design, functionality and details. Stuck to iPod touches until 2012 when I got an iPhone 5, got the iPhone 4S to bridge the gap between the 5 and 6 in 2014, and I still use the 6 to today (actually switched to a 6 Plus last week).
Instead of Androids many capabilities and customizations I like the simplicity of iOS. What I do most is just using apps, so that's basically just going to the home screen, selecting an app, exiting the app to the home screen, etcetera. That part always works, apps are of great quality and come in great quantities (I actually tried Windows Phone for a few months, can't say the same applies there).
Furthermore I use iCloud to have my things in sync between my Mac, iPad and iPhone. I didn't even restore the backup on my new 6 Plus, I just logged into iCloud and downloaded a few apps. Got everything right back including Photos (iCloud photo library) and music (Apple Music).
Hardware has always been great, not too fancy on the specs but just smooth and stable. Went to the Apple Store one time to get my screen fixed (dead pixels on iPhone 6), experience was great despite having to go there and wait for an hour (much to do in Amsterdam, luckily).
If my next phone would be anything different from an iPhone, I would probably want to (or have to) switch computers and tablets too. And services. Not going to happen. Don't mind being trapped in Apples ecosystem.