Agreed that this deal seems to be identical to that which arrived through my letter box yesterday and is available to anybody.
None of the ISPs consistently delivers the service advertised across the country; this will continue unless and until the Trading and Advertising Standards people grow some balls. Of course those of us on married patches don't have the option of cable.
Unless the ISP has its own eqpt in your local exchange (Local Loop Unbundled (LLU)), you will be purchasing a service which is actually provided by BT Wholesale, so you should expect less bandwidth than they provide for their own customers.
The view I take is that I only have to deal with one company if I lose my service, though I accept it's relatively expensive. I echo the comments here about Talk-Talk wanting to blame everyone else, based on the experience of family members.
STH