Up top, we've got a shot of all three phones. At left there's Michael, the retired bank robber with cash to burn. He owns an iFruit, the GTA world's version of an iPhone:
In the middle we've got Trevor, the psycho trailer-park crime lord, who uses what appears to be the GTA-verse version of a Windows phone:
And at the right there's Franklin, a gang-banger on the way up, who uses what looks more or less like a mid-range Samsung Galaxy clone (though as some readers have pointed out, the UI also has some Blackberry-like qualities):
I like a lot of things about these phones, first and foremost what they suggest about the characters: Of course wealthy Michael uses an iPhone, and it makes sense that up-and-coming Franklin would go for a cheaper Samsung. But what does it say about the crazed killer Trevor that he uses a Windows phone? Perhaps a subtle jab at Microsoft? The world may never know.
Really though, it's the little user-interface details that make the phones stand out to me: How Michael's iFruit has a "dock" at the bottom, complete with icon-reflections. How Franklin's Galaxy-alike displays his inbox count on a bar on the top, rather than in a badge on the icon. How the Galaxy displays its battery life in segmented bars, while the other two phones are solid batteries. The different graphics on the signal-strength meters. How they flip to landscape-mode to display emails. And so on.
Given the size of the rest of GTA V, these kinds of minor details can feel a bit beneath our notice. But the phones are a great example of the small, deliberate ways that Rockstar has drawn lines between their protagonists. Each time we use a phone, we're subtly reminded that we're inhabiting three different lives.