In a nutshell - Do not touch with a bargepole!
Like many others on this forum, I was suckered in by the deals they had to offer and assurance (after 3 calls before signing up) that we would not be charged setup fees... we were.
That was back in April 2007. Since then, it has been a very steep decline in service. "Broadband" speeds like a 56k dial up, phone bills for hundreds of pounds for services I've not used (wi-fi?!! WTF? Since when do you pay for your home wi-fi?), countless phonecalls and letters to their customer services team and I've NEVER had a reply... until now (I canceled my payment to them). The letter from them is dated 20th Dec 2007 and I recieved it today... 16th Jan 2008!!! I've got missing bills which have carried over to following months with no explination and I'm finally giving up on them.
I URGE everyone who's had the displesure of DST to get in touch with OFCOM, Trading Standards and CISAS. The more of us that do that, the better we all stand a chance of getting our money back.
PLEASE TAKE NOTE!
Grant