The Dergvale is close enough to walk to most of the sights. It is situated on the North side of the Liffey in a quiet and safe street. We were not bothered by noise from traffic or bars. The rooms are clean, quiet, nicely furnished and decorated (I saw two of them) with ensuite bathrooms and comfortable beds. About half of the some thirty rooms have no other rooms below or above them, which no doubt adds to the quietness at night and in the mornings.
We had an absolutely stunning 'a la carte' full breakfast (included) every morning. You may choose from three different kinds and we tried all of them.
Staff were wonderfully friendly and very helpful. We came back pretty late every night and were allowed to have drinks at that hour in the comfortable basement bar (guests only).