Does Guinness taste the same everywhere?

Listening to this morning's Excess Baggage on Radio 4, I heard Edward Enfield (Harry's dad) talking about his cycle trips across France. He described a visit to Montelimar, the home of Nougat. He talked about a visit to a nougat shop and said that "like Guinness, nougat tastes the same everywhere".

I see this is an idea, in relation to Guinness, encouraged by Guinness themselves. Their official website has at some time (I can't find it currently there) said this:

"Where is the best place to drink Guinness?
For some, the best place would be the pub, however, for others the comfort of their own home is best. Because of the company's dedication to the 'Perfect Pint' ideal, Guinness tastes the same everywhere."

But is that true enough to be repeated ad infinitum?

There are five different types of Guiness stout for starters: Draught, Draught cans, Foreign extra stout, Draught extra cold and original You can't say that they all taste the same. Obviously if the draught, or indeed the other cans or bottles, are not kept properly, then they will not taste the same as where they are kept properly.

When I worked at Courage's Berkshire Brewery (admittedly so long ago that I had hair at the time) I was told my an old hand that the quality of the bottled Guinness could be discerned by whether it had a brown or a green crown cap. The green was brewed specially for the Irish and was therefore superb. The brown was brewed for the English and was therefore not quite so superb. Perhaps this is a myth, but the bloke had been around in brewing for a few years. Perhaps the bottles don't have different coloured caps these days.

I am sure most people have also heard tell that the draught Guinness in Ireland is completely different from that in the UK. I have drunk it in both and the Irish stuff seemed better, but perhaps that is just because I prefer the Irish surroundings. Someone told me the other day that the Ireland versus UK difference occurs no longer.

Putting this all together, it is a bit of a generalistion to say "Guinness tastes the same everywhere" but I would welcome thoughts from more experienced beer-heads than me.