As I stayed in this hostel as part of the Paddywagon 6 day Southern Ireland tour, I didn't really choose to stay at this hostel. But I must say, compared to other hostels on the tour, this was one of the better facilities.
Clean dorms, Various breakfast options (Toast, Cereal AND Muesli!!) Good shower temperature, friendly staff, adjoining pub.
The food in the adjoining pub could have been better, my burger bun was burnt, but my friends were quite happy with their meals.
Some extra tips:
There isnt much to see in the town, and no ATM. Make sure you take cash out before you leave Killarney if you are staying in this place as part of the Paddywagon tour.
The showers are electric and need to be switched on outside the entry to the bathroom.
The keys need a good hard wiggle before they work to open the doors!