I've only scratched the surface - there's lots more Sendgrid offers. One of the nice things is that you can get an activity feed and some nice stats after you send an email to see how people respond:
|Activity Log, showing opens, clicks, delivered, etc.
|Stat report, showing email performance.
If you're a Google Cloud customer, they offer a free trial with up to 12,000 transactional emails per month. Definitely worth a checking out!