Since 2005 it has been brewed in the same place St James's Gate, so would be exactly the same product. Likelihood is when you've drunk it here it's been in pubs that don't clean their lines properly or often. In Ireland it is traditional for the brewery or supplier to clean the lines for the...
Drinking anything cold or indeed hot dulls the taste buds, therefore drinking Guinness 0% cold removes the flavour making it drinkable. It's the whole reason they started to do extra cold normal Guinness, in the hope youngsters would start to drink it. They only lowered the temp by 2 degrees but...