Sprint Offer Confusing Unlock Policy

Unlike the UK and some other countries, you can't buy an unlocked iPhone 4S in America. But now with Sprint you can, kind of, let me explain. When you buy and activate your iPhone from Sprint, the device will be shipped to you unlocked. but sprint have stated they will be locked the micro-SIM slot 'shortly after launch', so by the sound of it Sprint will send a SIM lock through to the device, meaning you can only use it on Sprint's international and domestic network. Sprint have said they will be unlocking the SIM slot for international use in 'good-standing' with them. Hopefully they will do it similar to Verizon and be able to unlock your phone after 60 days. So what do you do if you travel abroad? Well Sprint and Verizon iPhone 4S'  should work just fine, you can add-on roaming packages to your account which will offer you discounted prices overseas using GSM networks, which you enable in settings. So the world phone feature of the iPhone 4S has come into play with Sprint and Verizon both offering discounted roaming via add-ons and there international partners. But is it worth all the trouble, or are you just going with AT&T?