The lack of "double-click to add an entry <here>" is unintuitive - I've got very used to that action in iCal/Calendar. I would imagine that anything you can do to replicate the built-in calendar interaction would be a bonus.
Im slightly confused about who makes this app. This page is from "Mornings", but everything in the App store and in the App itself reference "Ready Tap Go".. I think the app is great, but I'd feel more comfortable if I knew whose App I'm giving access to my calendar data