Overall, our stay in Dublin was fine. The apartment is cute.
However, I've been reading other commentaries from other travellers and there is a recurrent problem that slithly ruins the stay :
The shower is a problem. We only had 3min to shower ourselves and EVEN THOUGH our host told us the water heater had to be repaired, this seems to be a recurrent issue. I think there should be a real investment in truly repairing or buying a new water heater.
Yes, the apartment is not expensive for Dublin, but still, I truly think having a good 7-8 min hot shower each day is the minimum. So please, for future travellers, do something.