I'm a multi-platform user, as well, so I'm still using several Android devices along with my 6 Plus.
My real adjustment is coming in navigating the OS, specifically the lack of the back button. I'm struggling with using the Pocketmags app right now; the only way that I know of to get back to having access to each issue of a particular magazine is to close the app and reopen it.
I've noticed that many converts say that apps are more polished in iOS than they are in Android. More polished in aesthetics doesn't equal better function, though. The Swype keyboard on iOS doesn't show the symbols on the letter keys, even though they are still there. One of my game apps doesn't calculate the score properly on my iPhone, but is fine on the Android phones that I can play it on.
Overall, I am enjoying the iPhone more this time around than I did when I had the iPhone 4. The larger screen and the choice of keyboards make the device usable for me now. I'm still missing full NFC functionality on the iPhone, though.