I don't know about the Guiness but we went there once. They are very full on, clapping all the time and trying to get you going.
I was only there to see the Elvis impersonator on that night. It was a member of staff with a wig and an inflatable guitar!
It's worth going once though just to see one of the bar staff balancing several cocktails on a tray on his head while climbing a tree across the road, he does this about 2 times an evening
