sbowness: Can someone give me some clarity as to what the "New phone every year" actually gives you. There is a mandatory trade in of the old phone. How much is that worth? What model of new phone will I get? It's very vague in both the blurb and the T&Cs. I want to know for sure that I will get like-for-like (or something even better) when the time comes.
I just rang 777 with a similar question. Basically you give them the existing packaged phone (currently the S4, HTC One or iPhone5) and they give you a choice of the current equivalent. The implication (and my assumption) is that its at least a like for like.
The thing you may have missed that's worth considering is that you'll have to resign for another 24 months at the end of each year if you want to take/keep the 'renew phone' offer. It's essentially a lock in strategy and a built in break fee all in one.