In a state of change
I only stayed one night so this can only be based on a brief business trip stay and there seemed to be construction work going on so not sure what the final thing will be like.
The greeting was excellent from the reception staff and I was personally escorted to the room. The room was a reasonable size and nicely decorated. It was described as have a 'city view' which was rather misleading as the only window looked out on the rather ugly side of a building across the road.
I arrived early so registered and went for breakfast in the Cellar restaurant. On the surface, it was impressive, but let down badly by poor service. I ordered toast - none arrived. My breakfast arrived so a reminded them about the toast. Waited a couple of minutes - no sign of the toast. Started my breakfast - which was not hot. Almost finished when the toast finally arrived. Good coffee and orange juice though...
Good, central location for walking the city and so, taking all things into account, I would recommend The Merrion so long as they get some of the details worked out.