I stayed in Pat's place when I was in Dublin for a work event. The location is excellent. I was walking distance to RCSI and Trinity, as well as the park and the famous streets with great restaurants and shops.
Check in was very easy - the Abbey Court Hostel is open 24 hours, so you can check in whenever you arrive in town. I was also able to pay a fee and store my luggage at the hostel so that I didn't need to carry it with me after I checked out of the apartment. There is also an elevator/lift, which I appreciated since the apartment is on the top floor.
Word of warning for light sleepers: the apartment is in the heart of a vibrant part of the city, near pubs with live music that plays quite late into the evening. If you are a light sleeper, this is not necessarily a quiet place to be, but the host kindly provided ear plugs to help with sleeping.