This is exactly what I've been looking for but couldn't find! Fantastic. Sendgrid strips HTML tags in their Template Engine but doesn't document it -- I debugged their WYSIWYG editor and gave them the source of the problem, but they asked me to send a video. After 4 rounds with support I had nearly given up on finding a good service that mashes developers with the marketing and design departments.
Three tips:
1. Please optimize your SEO! Searching for transactional email, transactional email service, transactional email comparison, I don't and didn't see you in results. (Guess I should have asked Hootsuite :)
2. I signed up from my mobile so I wouldn't forget -- your dash seems to work great except the gravatar/account is fixed position.
3. I tried to sign back in to confirm #2, but the log in link is nonexistent on mobile.
Congrats on the funding round from a fellow BC startup! Hope to see you around :)