The Guardian rounds up several notables to address this apparently undying question.
Will Self: I'm still not convinced creative writing can be taught. Perhaps you can take a mediocre novelist and make them into a slightly better one, but a course can't make someone into a good writer. Ian McEwan and Kazuo Ishiguru both did the UEA MA, but they were both innately good anyway. Some people swear by creative writing courses. I say, go and get a job, a fairly menial one instead. Otherwise what are you going to write about? Writing is about expressing something new and exploring the form in new ways. So unless you want to churn out thrillers or misery memoirs, you can't work from a pattern book. You need to autodidact.
As my students at UCLA already know is, my answer - maddening as always: It depends.