Stayed here for one night as it was a good location (5-10 min walk from las ramblas) and cheap for Barcelona. Most of the staff were really friendly and helpful, and gave us lots of advise for going to the airport. The common room could have been comfier but we're still able to meet other travellers there. Had a pretty well equipped kitchen, just a bit on the small side. Wifi was reliable and available throughout the whole hostel. Good security with decent sized lockers and someone always on reception.
Downsides were the dorm was really cramped and smelt funny. Also they charged extra for towels, extra sheets etc and it wasn't cheap.
Would maybe stay again, but only short term