http://www.theregister.co.uk/2013/02/04/bt_totally_unlimited/
So BT retail are confident their network can stand up to the challenge. I wonder if BT Openreach are as confident?
BSkyB made a similar statement which in the end they couldn't fulfil. They ended up with over subscribed networks in certain areas.
I had the misfortune of being with them for 18 years and would never go back no matter what they offered me. I was often getting download speeds of 104 kb/s which was little more than ISDN speeds. They claimed that was quite acceptable. Thankfully Rik persuaded me to switch to a far better provider. ;D
Since I moved to a O2 Wholesale based ADSL solution my line has been achieving speeds I never thought possible and has been rock solid.
Also I'm paying 15 quid a month (what I used to pay for dial up) for an unlmited service with no traffic management and last month I used about 45GB which is heavy use for me.
Unless I move and get s shorter line I'd not move back to a BT Wholesale based line again unless of course FTTC or FTTP becomes as cheap but even then not through BT Retail.