It's going to depend on what the fault is. If it's one that's known to them, like the discoloured screen or dodgy home button, then a sympathetic Genius is likely to replace it. Mine was replaced at 13 months for the home button issue with no hassle. and my iPad was replaced for free after I dropped it and cracked the touch screen. And I watched a girl get a free replacement after she dropped her phone twice, smashing both the front and back glass.
It also depends on how you approach them. I've always had great service from the Genius bar, and having spoken to a friend who manages a store, understand that their policy is essentially to delight the customer - but not if the customer looks like they're trying to pull a fast one. the quote from him was that they're always encouraged 'to do what Steve would do'. So a customer who demands something out of warranty almost certainly won't get it, but one who is genuine probably will. My friend had a customer recently who had had his MBP for months, but had so many hardware/software problems that he was simply getting angry with everyone involved through frustration, even though they sorted each issue. In the end, my friend went to a cupboard, got a new MBP out, and gave it to him. The bloke obviously thought it was an exchange, but it was an addition. He went away the happiest customer in the world that day, and has since been back, thanked them again, and has bought several more Apple devices, as well as, probably, told all his friends and colleagues about how good they are.
So, what's the problem with it?
Tiptopp
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Edit - Having read your recent responses, bearing in mind what I said, I'm not surprised you haven't had sympathy.
What's the problem?