Highlander prefers Jameson Irish Whiskey?

Tonight. we were watching Highlander the series, Season 2, disk 2. It was the episode Eye For An Eye and there is a scene where Duncan and Annie were drinking a liter of this brand whiskey. We would assume that immortals who had lived for 400+ years would only be drinking the best. And the producer and director of the episode would know this, and so we should also assume that that Jameson Whiskey is the best whiskey to drink. Do immortals suffer from hangovers? 😀