We spent two nights at Denis's place and really enjoyed it. We didn't actually meet our hosts, but the check-in was super easy and Denis always replied very quickly to any messages.
The room was beautifully decorated, super clean. We had a lot of useful brochures in our room and the bed was very comfy. The house itself was conveniently located between the centre of Killarney and Ross Castle, which meant we could walk everywhere. Moreover, it was very quiet and the room was spacious.
All in all we would definitely recommend Denis's place.