I also use Google Calendar, but in my experience sync between calendars across users is slow unless you send out invites for each event (instead of sharing a ca

I also use Google Calendar, but in my experience sync between calendars across users is slow unless you send out invites for each event (instead of sharing a calendar). Calenday is supposed to be a real-time solution (updates happen near-instantly). It also allows you to add the plan to external calendar apps, but with a delay (imposed by the external service). I hope for Calenday to implement features specifically for trip planning (although I am also trying to find other applications). Ideas I were considering are adding location-aware functionality like figuring out travel time and such.