Users appreciate the Postmark WordPress plugin for its reliability, simplicity, and efficient support. Many have found it a robust solution for transactional emails, outperforming competitors like SendGrid, MailJet, and Mailgun. It integrates seamlessly with popular plugins and offers straightforward setup and configuration. Users note that it saves time and reduces email deliverability issues. However, some have reported compatibility problems with various WordPress versions and issues especially when used with WooCommerce. Despite these drawbacks, the overall consensus remains highly positive, with users valuing its dependable performance and responsive customer service.