Good in Parts
I use choose and book daily as a doctor. It takes me longer to make an appointment for someone. It's less flexible for me and the hospital, and I have to meet a target on using it: frustrating when some days it just won't work. No-one on the health-care side finds it helpful.
Last year I had occasion to make my own appointment. No luck on-line. Call Centre helpful but apologetic. I phoned the consultant's secretary to sort it out.
Bottom line - nice for the public when it's working. much of the "choice" is illusory. It was mostly introduced as a tool to stimulate competition between health providers. It's poor value for money unless you look at it from a political angle.
(Now don't get me going on your medical records and the spine!)
white coat, door...