well im irish so i guess i'll throw in my say, guinness is much nicer, much creamier, leaves your poop black as fuck and was made pretty darn close to my house in ireland so i vote guinness
Hmm.. I'm still undecided on this. Given that I live on pretty much the other side of the planet from where both beers are brewed, I'm sure my samples are a bit less than fresh by the time they reach me, pasteurized or not.
I have to admit I'm more of an IPA kind of guy, so I might not be the best judge of Stouts, but so far even after having a pint of Guinness from the tap at a local "Irish" pub (In Newport, Oregon, U.S.A., mind you), I think the cans (!) of Murphy's were a bit more impressive to me. Seemed to have a bit more flavor. Further testing is in order.