I am a Guinness addict. I'm a homebrewer, and I've tried 3 dry Irish Stout kits, two of which are supposed "Guinness Clones", and nothing has ever come close.
I think while a lot of it has to do with Guinness being the best widely available stout on the market, a lot also has to do with guinness including the nitrogen pill or whatever in the bottle. Before, when you crack the bottle, the change in pressure released a tiny amount of nitrogen into the beer, creating the storied "waterfall" and giving the beer the amazing texture nitrogen gives, as opposed to CO2. No, it wasn't the same as "On Tap", but it was as close as you could get.
That's all gone. Now they're starting a new 'straight from the bottle' deal (before you had to pour into a glass). Now I'm all for giving everyone the chance to sample the wonder that is Guinness, even if they don't have a pint glass (preferably clear) handy, but the beer is suffering.
I bet one of my clones can pass the "pepsi challenge" right now, and that saddens me.