As somebody who has used Sky, TalkTalk and BT, and has active both a TalKTalk line and a BT FTTC line right now, I have to say, they're all the same.
TalkTalk is great, only negative is 2Mbps upload, but I personally never notice it. Their router seems very good at ensuring things work even when I am uploading to dropbox etc.
I have no idea of SSE, personally I would not risk it. I would however not be afraid to leave.
BT should be able to offer £10 for infinity 1, it seems a very standard offer.
EDIT: TT CS sucks, but so does BT.
Edited by ukhardy07 (Wed 22-Jun-16 10:17:57)