Are US Consumers Better Off Buying an Unlocked Phone?

Unlocked phones have been a mystery for a lot of people who prefer to have their phones more affordable, and thus tied to a plan with a service provider. However, now that Apple has made an unlocked version of the iPhone 5 available, I wonder if it is just a ploy by Apple to make more noise for its phone's rather disappointing performance. They have even cut down on orders for iPhone 5 parts, right?

On the other hand, does the availability of unlocked phones even benefit consumers at all? I am thinking this would be fine for customers who want to choose their own service providers. But then, the CDMS-GSM thing comes to mind again. So, if I buy an unlocked phone, which should I choose? AT&T? Verizon? Sprint? I wonder if it makes any sense for the customer at all. I mean, does it save me money in the long run if I buy an unlocked phone instead of getting one from AT&T?