I've stayed at High Street before and enjoyed my visit both times. Its clean and the staff is very helpful and entertaining. There is a small kitchen that you can use for food prep- microwave, hot plate, and fridge. The rooms and girls restroom/shower room were kept clean and tidy. It would be nice to have the Wi-Fi in the rooms as it can be a bit difficult to find a place to perch in the main lounge/kitchen areas at certain times of day.
Great location across from Borough Market and just down the street from the Tube stop and London Bridge. Wi-fi in the room can be spotty from time to time, and the password to log on is a bit of a nightmare to figure out the first time. Staff is very helpful, they know the city well, and were even kind enough to make a reservation at a local Indian restaurant when we inquired about good places to eat. The in-room lockers are large enough to fit just about any suitcase.
Overall this hostel isn't bad. It's located right on the river within walking distance of O'Connell Street and the Airlink stop. Overall the hostel is pretty clean, you collect fresh sheets at check-in. My only complaints were that the pillows were about as thick as a folded t-shirt, and there were no lockers in the rooms themselves (small lockers for valuables are available downstairs though).