This place is famous as the best place to stay, on either side of Iguazu Falls (Brazilian or Argentinean). It was recommended to me by several people in Buenos Aires — and it's so big and so full of tourists, it seems that I'm not the only one that got a recommendation about it. Everyone in town comes here! And with a BBQ dinner every night, live entertainment in the evenings, free Internet and Wi-Fi, a big well-stocked bar, daily tours to the falls, and a huge swimming pool, why would you go anywhere else? The place is more like a resort than a hostel, really. Considering that it only costs about US$10 a night, it's a ridiculously nice place for a travel-weary backpacker to crash at. Hostel Inn: a part of the Hostelling International network.
Rooms: quite comfortable, located downstairs and away from the noisy bar and common area, and not too crowded.
People: every man and his dog that's come to see Iguazu Falls is staying here. Backpackers from near and far, a few families, a few couples, a bit of everyone really.
Staff: very professional, all English-speaking, and available all the time.
Location: not the greatest — a fair way out of town, so you have to get a bus or a taxi to/from the place — but at least it's quiet and peaceful out here.
Food: great buffet breakfast of cereal, bread, fruit, and tea / coffee / juice. Plus, the all-you-can-eat BBQ dinners are sensational: see how much asado (beef) you can stuff yourself with!
Internet: 5 PCs with a good connection (actually 5 isn't that many, considering how many people there are here). Plus, plenty of laptop-owners take advantage of the Wi-Fi.
Hot water: strong and reliable.