I stayed at CaipiHostel for a week during the World Cup and I really enjoyed it. The atmosphere is very hip and clearly geared towards young travelers looking for a party scene. The staff was generally quite helpful and all spoke English. Each bed's headboard has two power outlets, which is nice because it's made for travelers. The location is about two blocks from Lapa, a big party spot, and the hostel threw a party on Saturday. The price was high for a hostel, but it was during the World Cup.
I appreciated the helpfulness of the staff, but didn't feel like I was really part of a fun community during my stay. I'm not sure if the AC didn't work in my room or if it was simply not turned on, but that would probably be an issue in the summer months. I appreciated how clean you kept your hostel.
My friend and I stayed here in June and we were blown away! The facilities were modern and clean, offering multiple kitchens, bathrooms, showers, and common rooms. There is complimentary wifi and several computers available for use. Tat was the employee to check us in and she was very helpful giving us directions and tips during our stay in Barcelona. The staff organizes pub crawls nightly and it makes meeting awesome people at the Sant Jordi Hostels easy and fun. I hope to stay here again!
The staff puts on fun get-togethers most nights that the whole hostel can attend. Salvatore spaghetti disco is a great time and always leads to a fun night out. The breakfast is basic, but is still a good deal for 2 euros. Locks and towels can be rented for 2 euros also. Lockers are small, about 2x2x2, so most baggage is kept unlocked, but we didn't have any problems with theft. Met a lot of cool people, wasn't bad for a youth party hostel for the price. Lockout is from 11-16 daily.