In the market for a new phone topic

As above, I'm currently buying a new phone;
Right now I'm deciding between iPhone 6 and Xperia Z3 (coming from Nokia N8). Basically, being able to stay with the same phone for at least next 2 years is very important for me, same goes for a good camera. Among things that iPhone does better than xperia is 240fps recording. Would it be possible to capture 240fps video with Z3 and some software modifications?:...

And to the most important part - android. I have no idea how to use it, never did. Is it easy to get used to, how many apps and stuff?...