Just be aware that there are plenty of asterisks (the code is the carriers' idea, after all). If you're the customer of a prepaid brand like Cricket or Virgin Mobile, you may have to wait up to a year and keep service active to a "reasonable" degree. Also, Sprint will only unlock your phone for domestic use if it's a model released after February 11th; anything earlier is limited to international access. You're bound by the limits of cellular technology, too. Verizon unlocks GSM service on its phones as a matter of course, but you can't switch from GSM to CDMA unless the phone has supporting CDMA hardware (like the iPhone 6 or Nexus 6). And with few LTE frequences shared between American telecoms, you'll likely lose fast data.
It's important to note that you don't have to go through your telco to get this done. Thanks to last year's cellphone unlocking law, you're allowed to get your phone unlocked without your carrier's explicit say-so. The catches? You'll almost certainly have to pay, and there won't be much consistency in their policies. The big advantage of the code of conduct is that you now have an easily accessible and reliable (if not always trouble-free) way to jump ship with your existing handset.