It sounds to me like it comes down to whether you value / require AppleCare or not.
Buying outright and selling each year, without AppleCare, would always be financially beneficial...
I've never gone for AppleCare before, I've dropped my iPhone several times and luckily never damaged it. That said, the new AppleCare prices do mean it makes more sense imo than at any other point in the past.
It is definitely a shame they don't do the upgrade programme without AppleCare (I know about iPhone Payments).
I think, when push comes to shove, at my reservation on Friday I'll probably take the upgrade scheme. Much easier, and will be nice to not treat my phone like my child. I got stung a few months ago when I dropped and smashed an Apple Watch, and that was not fun.