After nearly 5 years of having a "normal size" iPhone (4 through to the 5S), my wife now has an iPhone 6S Plus, and wonders how she ever managed with a smaller screen. The Plus sized iPhone looks even bigger than my Galaxy Note 4, because of the extra space below the screen needed to fit a circular Home button.
Me, I'm sticking with Android for now, even though Apple have had 2 models of big screen iPhones. I've nothing really against the iPhone or iOS, and I would say that it's a good choice for a lot of people (it Just Works), but there are a few negatives..
1) No Wi-Fi scanning apps. You can't see anything like
and this is a definite NO for me. This is the number one reason I won't have a phone with iOS. I know jailbroken phones can run this kind of thing but why get an iOS device in the first place if Android phones can do it with no mods? To most people this wouldn't make any difference but as somebody who is interested in radio stuff, not being able to get detailed information about radio frequency signals such as channel number is no good.
2)Limited file management options. It's not easy to work with files on an iOS device that have been created somewhere else unless they arrive through some cloud service. Moving photos off to a PC/Mac to free up space is easy but putting them back on isn't simply the reverse of that process.
I do have one iOS device of my own, which is an iPod Touch (6th generation 16GB), that is normally in airplane mode and used for playing music when I'm out of the house. It sometimes goes online though, if I want to put my phone on charge when at home I'll use it as a standby "phone". I've used iPods for music for over 10 years (started with an iPod Mini 4GB in green), before there was iOS or iPhones. I found that it was actually better not to have a music player that was just a dumb removable drive, as with a large music collection, things like play counts, ratings and smart playlists mattered. There isn't a popular non-Apple standard for managing this kind of data, I can't plug a USB drive of mp3s into my car audio system and have it write to a file with the time that each one was played or whether I skipped it, then have my smart TV play only the ones I'd not played in the last 7 days.
Maybe in a few years the patents will expire for everything an iPod does and somebody will have a go at it, but by that time it will all be done through streaming music apps.