We booked a double room with breakfast included. The room was large, clean, modern and had a lot of amenities including fully working aircon and a fridge. The bathroom was very nice with a large shower and the bed was comfortable. The only slight downside was the noise of the elevator which we cold hear from our room but it really wasn't a problem. The rooftop bar, hot tub and "pool" (small but perfectly formed!) Was fantastic and there was a happy half hour 7-7:30pm every night with free caperhinias! The staff were friendly, helpful and really attentive. Breakfast had a large selection including fruit, cereal, bread ham and cheese, and hot options (sausage and a kind of omelette), coffee, tea and juice. The hostel is also very sociable with several common areas including the rooftop bar. The hostel also has an in-house tour operator offering airport shuttles (cheaper than taxi) and tranfers to and from the falls (we used then for the argentinain side which was great as they sorted everything re crossing the border). Supermarkets and restaurants are within a 2-10 min walking distance.
Overall an excellent hostel and I'd reccomend it to anyone going to Iguazu!