The Passwords are all the same arn't they?I did it and it was relatively painless.
Few things to watch out for is when setting up the modem your asked for a password which they did not give to me or email me (even though when ringing about it they said I should have been given one) so I had to wait a day for this to be sorted.
Also the first few bills I got were all over the place in the sense they were biling me for the incorrect packages and calls. This took few bills to sort out but I did get a letter of apology and a nice box of handmade chocs.
So far so good.
Worth it financially if you get the phone package - well it is for me.