Pricing is competitive. They offer A/B testing for transactional emails, which I had trouble finding as most of their competitors only offer this for marketing emails. The golang library is quite decent; we were up and running in under an hour. I had a couple of questions which was answered quickly and competently via chat.
MailerSend is a powerful transactional email system built for developers but designed so non-tech teams can contribute without coding. Intuitively-designed tools like a drag & drop builder and dynamic content templates help teams collaborate.