Thanks for the link Raggy - great stuff and very informative.

Can a pint of Guinness vary between pubs? Perhaps it can. Some places pour the Guinness as if it was a normal pint of bitter. Go to Ireland and see how they pour it there (order two if you are thinking of having a third and or order the next one when you are halfway down the first) they take their time, pour just over half and let the beer settle completely before finishing the pour. As stated, the cleanliness of the pipes etc must make a difference, so it is entirely possible differnent pubs could make a difference.

As for American beer, when we were in New York we found a microbrewery bar smack in the middle of midtown Manhattan, right under the skyscrapers that brewed a superb pint of bitter on site. I can't remember the name right now but was in the vicinity of 56/57th Street and Broadway. So it's not all Duff!