We use SendGrid for sending transactional emails to the users of our Chain SMS service. This includes emails like verifying your email address, welcome emails and password reset emails.
We recently switched from sending emails using an Microsoft Office 365 email account to using SendGrid. Here we've changed our approach from consuming a lower level capability (we used an SMTP interface to the Office 365 account) to consuming the higher level SendGrid service which we interact with using their C# client library.
We gradually rolled out the change to our user base and measured the % of users confirming their email address to estimate email delivery, we found SendGrid performed at least as well as an Office 365 account.
We found using more advanced email confirmation (SPF, DKIM, etc.) has made a significant improvement to delivery rate (increased the delivery rate by 10%).
We've also found that the email activity feature in SendGrid (which shows whether an email has been delivered, bounced etc) is particularly useful and has helped us learn more about how emails can go wrong (e.g. hard/soft bounce).
