Cons: I arrived at 11 am, after a long flight, was very tired and wanted to have just to have a few hour sleep and I couldn't do that because no one was there. I got information that check in time is at 15:00 only after arrival at the hostel. They did say that in the confirmation email too, but it doesn't make any difference, since you finding out that the purchase. I had a next plane at 17:00, so I payed the money and couldn't stay. Interesting stealing system - they don't give you information that check in time is after 15:00 before the purchase and the purchase is not refundable! I requested them to return me the stolen money and they refused. There is another student there as well, who was also uninformed by this weird 15:00 check in time!
Pros: The bunks were the best out of any hostel I've stayed at. They were completely closed in with a curtain that both added to privacy and shut out the hours of daylight well into the night. The kitchen was clean all the time, and the bathroom facilities were great.
Cons: The location is a bit far from anything other than a few supermarkets and a noodle station and bakery right down the street, but once you get used to the layout of that section of Hafnarfjordur, its a great place to stay, and my friend and I liked it better than the hostels we stayed at in reykjavik