In reply to goldmember: when you say superfast I suspect it will be fibre to the cabinet or fibre to the house depending on whats available where you are moving to.
bt and sky are much the same ie not brilliant but you get there eventually if you persist, talk talks cust service is dire and I would avoid, plusnet although owned by bt seem to get the best feedback ive heard.dont know about ee.
deciding if its worth paying the extra for fibre depends on how fast you would be on copper (which depends mostly on how far you are from the exchange) and how fast you would be on fibre (which depends on how far you are from the street cabinet)