We switched to Co-Op about ten years ago.
Yes, it seems a daunting task to change bank accounts but it's not that bad. DH and I split the job of advising everyone of new account details in half and it was done in a couple of days. Some things had been running for ten years or more and we'd mislaid contact details etc but we managed.
I can recommend the Co-Op. Apart from the ethical aspect, which was our main reason for switching, they haven't (so far) fucked up at all. And now the C&G down the road from my office is going to become a Co-Op I also have a branch nearby I can walk into if I need it.
I think this new deal with Lloyds, coupled with the overall distrust of most other banks, is going to bring Co-Op an awful lot of new business.