Cash advances on credit cards

I’m writing an article for “U.S. News & World Report” about cash advances from credit cards. If you’re a credit card expert or personal finance expert who has thoughts on whether it’s a good idea or a bad idea to use them, I’d like to hear from you. I’d also be happy to hear from some regular credit card users who have used cash advances – and if you could share why and how much interest you had to pay and if you were glad you did it or wish you had found a different way to get cash.