I went to Interlet 2 weeks ago because I had enough of looking for a flat myself. They greeted me in very professional and friendly way, then blonde lady offered me some properties to view same day. She explained everything very precisely. She also informed me that not all properties they have are in great condition but if somebody doesn't have high budget need to compromise on something, which I believe is fair enough. I went for viewings and I found nice and neat room in Kensington next day.
I will definitely recommend their service to people who want to find good place in London.