It is indeed impressive-- when the sun is shining! We were invited to New Grange about 14 years ago and on the day we were there it was horribly overcast and positively pissing with rain. The effect was that of sitting in a damp, dark cave, shivering with the cold, and wondering why we had gotten up at O-Dark Hundred Hours to drive for two and a half hours to huddle in a megalithic tomb... BUT... had the sun been out, it would have been an absolutely incredible experience.