Just user experience ...
Please keep in mind Subscription to TalkTalk means LLU (Local Loop Unbundling) which means TT now own the copper pair and Telephone number.
It is NOT an easy task to switch supplier expecially if you wish to retain your Tel. No.
Ok, TT Broadband is free (well not really). It takes a little tweaking to get running at an average browsing speed. MTU changes, DNS entries etc.
It's bargain basement so don't expect anything spectacular EVER
That said and done it's very cheap and if you can live with some instability at times then it's certainly worth a thought.
Good Luck
PS Had I been fully aware of LLU I simply would not have switched.