These day they are all pretty much the same where customer service is bottom of the list. I move pretty regularly and have discovered that if you owe a company money then they can block any move to the new supplier, but if they owe you money under the Energy Switch Guarantee companies can take up to 6 weeks to issue you with a final bill/statement and a further 2 weeks to issue any refund. Why ththe is is the case in this day and age i have no idea as I await responses from both Energy Switch Guarantee contact, Ofgem and the energy minister.