Friendship hostel is located in the very centre of the city, on the second floor of residencial building, with 24/7 reception. Wi-Fi is really good, rooms are air conditioned, with balcony and windows. Looks a bit old refurnished but still it's clean and nice. Staff is excellent, warm and welcoming, speaking fluent English an ld Russian. They can help you to arrange sightseeing tours inside or outside Yerevan.
Overall I would recommend this hostel for other travellers