Resend is developer friendly and was easy enough to setup. Mail delivery has been reliable and I like that I can see every message I sent on the dashboard. I especially like the template designer and have a dozen templates setup that I call from my app. Templates include embedded variables for personalization. Resend keeps coming up with new improvements and features so they're actively developing the product and service and they are responsive to feedback. Review collected by and hosted on G2.com.
The templates designer takes some getting used to and is not quite a WYSIWYG interface and adding links could be easier. Review collected by and hosted on G2.com.