we didn't do dinner, just the show. We had dinner at the very nearby Legends restaurant. I don't really recommend it. it was good, but kind of expensive, and the service was sloooooow.
the show was great! i was really glad we stayed a night in Cashel to see it.
One of my clients had the dinner at Bru Boru and said she would rather have skipped it and eaten elsewhere. I suggest Hannigan's Pub or if you want something more elegant and expensive Chez Hans. Legend's has been bought by new owners and is coasting on the old reputation.