I've been using iPhones since they first came out in 2007, and just got the iPhone 6 (and am quite happy with it). I don't get a new one every year, but every 2 years (I've had iPhone 1, 3GS, 4, 5, 6)
Here's the first one next to my newest one -- the 4.7" size is finally just right!
I think the 6 Plus (5.5") would be too big for me -- I like to keep it in my pants or interior jacket pocket, and this still fits even in a shirt pocket.
Are these phones perfect? Of course not -- no smartphone is perfect. But it fits my needs, and I'm generally happy with it. I can't bash Android because I've never used one, tho many bash Apple having never used one, either. Hmm.
I also am happily stuck with AT&T as I'm grandfathered-in with an unlimited data plan that I can never give up at this point!