Having previously worked for a mobile company, I’ve had every phone known to man. It is an adjustment, but easy once you have gotten used to it. As mentioned by PP, some things are better and some are worse.
iPhones are designed to be “easy” in that they’re designed to just “work” and the syncing between iPhone, iPad, Apple TV or PC (if you have/use these) is just done and there is no messing about setting one up to work with the other and then doing it again for the next device.
Because of this, Apple have a lot more sway over how their phones work and even how they look on the user interface - they’re not nearly as “open” as android (as in being able to customise layouts, themes, what document and file programs you can use etc). Of course the main day to day apps (social networking, browsing the web, music apps etc) are pretty much the same.
But the upside of that is Apple phones are more secure than Android will ever be, eg EVERY app on the Apple App Store is screened by Apple before being put on the store for download, so the chances of dodgy developers sneaking an app in that can snoop or get personal info off your phone is slim.
One note, whilst the iPhone 6 is still a very good phone, and fine if you still have one and use one today, I’d be more wary of getting this phone as “new” now, that particular phone in iPhone speak is 4 generations ago and was released 4 years ago, so if you are looking to get a typical contract length of use out of the phone (2 years) then in your second year of use, it will be a 6year old device, and yes, Apple DO slow down handsets when software updates are done and newer models are available.