I evaluated it here in UK and it just didn't make sense for me. It was very expensive -- slightly less than buying a phone every year, but much more than doing it every two-three years.
The iPhone Upgrade Program is exactly the same price over the full course of the loan as just buying the phone with AppleCare. If you don't want the AppleCare, "iPhone Payments" is exactly the same price overall as just buying the iPhone. Both are 0% financing.