I'd have liked to see some sort of screenshot tour (or a product video as there is presumably a real-time component) before signing in - there's very little detail available, which might be good for conversion, but it meant I didn't click the button.

(When I did, I was given a "sign in with Google" chooser - did you consider telling people what is going to happen before they do that? It might seem obvious, but it might put people off too.)

Also, have you considered per-domain pricing? With the demise of Appointment Slots, this could be something you could sell to a Google Apps for Business customer for all their users.