I'd like to clear this up once and for all. Let's only cover the iPhone 5S and up. Is there a difference between an unlocked iPhone between all carriers? Is a Sprint Unlocked iPhone 6 better than an AT&T Unlocked iPhone 6? I've fallen out of being in the know. I know Verizon iPhones are all unlocked out of the box, but are they better than an AT&T Unlocked iPhone for any reason? Would an AT&T Unlocked iPhone work on Verizon/Sprint? I know Verizon phones work on AT&T and T-Mobile. (Do they work on Sprint?) and I assume they have restrictions? (No Visual Voicemail?) I once heard that Sprint was the "True Unlocked" iPhone, and supports the most bands. I've also heard the same about T-Mobile phones. I'm genuinely confused by it all. I am still in the old mindset that Sprint won't unlock their phones domestically (not true anymore) and that AT&T unlocked iPhones won't work on Verizon and Sprint simply because Verizon and Sprint will not activate them (not true anymore) So can someone please clear this up for me? What is the best carrier to have an unlocked iPhone from? If you buy a "sim free" iPhone from Apple directly, which model is it? What are the differences? Thank you so much.