Few things
1. You say on the site: "Start your 14 day free trial" but there's no clear pricing, so what happens after 14 days?
2. People are visual, I'd put a whole flow in a gif, something, with the picture (screenshot) of the email that's being sent to the client.
3. If you have plans for integration with popular systems, like Trello, Github, Basecamp or others, I'd put logos of those with "Integration coming soon"
4. Inside the systems, the Preview of the emails are too long, when you have a project you usually need 10-20 reminders, I'd cut the length of the preview to 200-300 chars and have a separate page for each of those. (also add an edit option, so if I have a typo, I can fix it easily).
