Having done similar things in the past myself, decided not to in future because I really don't want to be without my iPhone for 6-7 weeks. If you look at the unlocked machine, I calculate it's worth $94 depreciation alone (if you assume you upgrade every year so use an accelerated depreciation schedule) so I'd rather sell the phone 1 day after launch even if I get $93 less when I get to sell it. In fact, I'd rather get $120 less because being without my iPhone for 6-7 weeks is worth at least $27 to me (in reality a lot more than that!)