Staying with Joan and Leo was a great choice. They are wonderful hosts, warm and welcoming, gave us great tips and always offered their help. The house is very lovely, with a separate room and en-suite bathroom for the guests - clean and decorated nicely. It is located in a quiet and safe neighborhood, but still very close to the city center, only around 15 minutes by bus. Also, there a some nice shops and restaurants in direct walking distance to the house.
I can absolutely recommend staying with Joan and Leo.
I will definitely come back to Dublin and their place will be my first choice to stay.