Bradleys on North Main Street is the offie of choice for good quality beers in Cork.
I know what you mean by the Blackrock Stout and the herby tinge, it can be a bit hit and miss if its not fresh, but get it fresh and you won't be disappointed! I take this as a good sign, because it means the stout is "natural" (for want of a better word) and not full of preservatives.