I really enjoyed London Backpackers. The beds all had their own power points and lights, as well as curtains for privacy. The common rooms were always full of people and the staff were helpful. The only downside was that as far as I could tell, there were not a great deal of bathrooms for the amount of people, and it was far from the centre. Having said that- it was directly opposite to a tube station so that wasn't a huge problem. All in all I thought it was great!
Great hostel if you are travelling with friends or just want to chill out on your own for a few days as the rooms are single. Not so great if you want a party or social atmosphere and like to meet new people. There are lots of kitchens and there seemed enough bathrooms. The common area smelled very musty and unused which I imagine is why not many seemed to use it- to encourage people to use it, this could be addressed.