It depends what you want.
If you want an almost guaranteed problem free service with UK based customer service and intend to use P2P a lot then TT is not for you.
If you don't mind a gamble and don't mind using the members forum if you have problems (phone support can be useless) then i would say go for it.
I have been with TT for nearly four years and will be staying with them for the foreseeable future.
They have just made their essentials package unlimited (used to be a 40GB cap) but it does say they will remove unlimited if you abuse it.(see below)
* Unlimited Broadband TalkTalk slows down non-time critical peer to peer file sharing at peak times, to ensure the best internet experience for all of our customers. Promotional unlimited download allowance is subject to availability and maybe withdrawn at any time. Fair usage policy applies to unlimited download allowance. Please visit talktalk.co.uk/fairusage for more details.