A 12 hour non-stop tour sounded a bit hardcore in the beginning, but after having it done, I cannot recommend it enough. It may have something to do with the fact that we might have had the best tour guide I've ever had. Of course, I'm talking about Jamie! I found the way he narrated the information regarding the tour superb, very interesting bits of Irish history, I've could have heard it all day long.
But even without an excellent tour guide, the tour itself it's worth way more than what it's paid for! Only the cliffs are an astonishing view. I guess it also had to do that on 18/04 we had the best possible weather (although it was not the 'real Irish experience') one could have.
All in all, 10/10 tour, 100% recommended to anybody