Mandrill has been pretty reliable. I was certainly annoyed by the pricing and sending requirements change, but the actual cost didn’t increase much for us since

Mandrill has been pretty reliable. I was certainly annoyed by the pricing and sending requirements change, but the actual cost didn’t increase much for us since we already had a Mailchimp account. That said, we have a duplicate of Mandrill’s sending infrastructure at SES and use it enough that we know it is ready for migration. We have a lot of domains (agency.) Keeping track of domain sending security for two providers is occasionally challenging, but we could move everything to solely use SES in about a week if needed.