I can't wait to see previous arguments against large phone screens flip, at which point all the fanbois will be praising Apple for the larger screen "innovation" and claiming that small screen smartphones are stupid, and then go on to claim that Samsung was just copying Apple.
I'd go back to the iPhone if Apple were to include a MicroSD slot and make the battery user-replaceable. Based on what I've seen so far, it's taking a huge leap backward - it was very quick and easy to replace in the iPhone4 (mine is on its second battery) and even the iPhone 5, while not as straightforward, is relatively easy - but typical users would not be able to or would be too afraid to attempt swapping it out.
The iPhone 6 looks like it is heading back to iPhone 3GS-style construction with the battery located underneath everything else (based on appearance of leaked backs/chassis). I hope I'm wrong about that though, and that the battery ends up above the logic board.
What keeps me away from the iPhone: no MicroSD slot, no user-replaceable/user-expandable battery. What keeps me with the Galaxy: user-replaceable/upgradable battery (I have a 7500mAh battery in mine) and MicroSD slot (I currently have a 64GB card - will be getting a 128GB card soon then I can have my entire CD collection on it, re-ripped at high bit rates), plus I have full access to the filesystem rather than the very limited, abstracted view Apple provides (why CAN'T I have apps share data if understand the risk and I WANT it to? It's
MY phone,
I want control over file management!).
Oh, and I LIKE iTunes. Samsung's Kies sucks. Lots of technical people (techs, sysadmins, developers, etc.) despise iTunes but I think that it does what it is intended to do very well. I don't like the back end (flat file structure IIRC) but the front end is very good for managing the iPhone, whereas Kies does a middling job of it.