I have to say I found estate agents quite useful (mostly when I was renting). I much preferred dealing with a letting dept. of a reputable estate agency than random landlords. Yes, I had good landlords(funnily enough when I was quite poor in the cheapest accommodation possible), but I had bad ones too. I never had a bad renting experience with an agency. Stuff always got repaired on time, cleaners got hired to clean common areas, electricity and gas got inspected regularly. All those things are not a certainty with random landlords and you only find out once you've moved.