LLU = Local Loop Unbundling, which means the ISP has there own ADSL equipment in your exchange.
Some are good, others are bad.
Bed/O2 are good at the moment. O2 got into broadband by buying Be and using their stuff. Be had very few customers for the kit so performance was brilliant. As O2 marketing gets in the customers, who knows what will happen? It may get over-loaded, or O2 may provision extra kit to cope.
Sky/UKOnline seem quite good, specially as Sky is very cheap if you have Sky TV. But Sky Connect, which is not LLU is very poor.
TalkTalk opinions vary a lot. For low usage probably OK.
Tiscali/Pipex is a disaster area.
All other "up to 8Mb" services are supplied through BT Wholesale, so when you check your exchange don't think that means you can only have BT or the LLUs, you can have pretty well any ISP.
Edit:- If you use the checker TK linked you to, there is also a mapping system to check your area.
Edited by RobertoS (Mon 03-Mar-08 15:05:55)