We were staying here for 3 nights. There was no need for check in, we could accommodate without getting in touch with the host, so we could arrive at any time we wanted.
The room was small, but comfy and cozy and provided all the space we needed for three-night stay.
The best thing about staying at Sonia's place were breakfasts :) In whole Dublin you wouldn't find better breakfast than the one cooked by Marco and Sonia.
Summing it up, we were very satisfied and we would recommend it to anybody who wants to visit Dublin and doesn't care about the distance between accommodation and city centre (Dublin is easily accessible by Dart train or bus).