With no LLU there, makes no odds. It'll all be the same: BTw resold.
Anyone who has had TalkTalk on a BT exchamge would know that all ISP are not the same
To me it is all about size of pipe used by ISP and how it is filled. Overfill. like TalkTalk, and problems occur. The better ISPs manage pipe and increase size to ensure no overfill. This may mean extra cost to consumer but out weighs overfill option