While a GSM unlocked phone sounds attractive, there are market problems. Not all wireless carriers are created equal. AT&T and Verizon have the largest networks

While a GSM unlocked phone sounds attractive, there are market problems. Not all wireless carriers are created equal. AT&T and Verizon have the largest networks, but they use incompatible wireless technologies, so an unlocked device grants you no mobility. Yes, you can move to providers like T-Mobile, but that's not a 100% equivalent comparison. Depending on your needs, you may still be locked in to AT&T or Verizon, at which point an unlocked GSM phone nets you zero savings. My point is that it's still not a "common sense" evaluation. It's a nuanced decision that must consider all variables.