My husband and I traveled from Canada to visit Ireland and our first stop was in Killarney for a couple of days. John's place was centrally located and we couldn't have asked for better in that aspect. The place had everything we needed, except for maybe a fan and some face cloths. It got very warm overnight even though it wasn't very hot outside. We kept the windows and skylights open the entire time we were in but it did get very noisy from the nightlife at night. There are nightly street performers until about midnight and people on the street until 4am so bring your earplugs!
There are a couple flights of stairs leading up to the apartment so it would not be ideal for people with mobility issues, lots of luggage or small children. For us it was okay.
The check in and out were very easy. We were able to walk from the train station (10 mins) and meet up with John's sister in front of Murphy's ice cream shop.
Killarney is very touristy, quaint and overall really lovely. There are a few things you can visit and we did a tour with Paddywaggon that took us to Dingle and slea head which I highly recommend. Overall our stay was pretty good!