Hi there, I have a genuinely faulty (and still under guarantee) 3GS, that I have been meaning to take to my local Apple store in the UK to be replaced. However, now that the model has been discontinued, is it worth holding out for stocks to run down in the hope that they replace it with a 4 - or will they only ever exchange like for like? How long would you predict it will take for 3GS supplies to run dry? I'm not trying to pull one over on them, just want to ensure that I'm not going to be lumbered with another duff 3GS. Many thanks!