I used Extra Energy over a period of years at two properties and I was well impressed. I would happily recommend Extra Energy. The prices were rock bottom and I saved a packet compared to my previous supplier EDF whose service was as bad as the prices so EDF is off no matter what. I've moved house again and this time the property has prepayment meters in it and as soon as I get them out I'll be be going back to Extra. Strangely though Extra is not coming up on the price comparison sites. My only gripe with Extra was the 40 minute wait I had on the phone once when I was moving house which was annoying.