After browsing through the API, it appears that comments are treated as a completely separate entity from the event they are part of. Consequently, when I do a query using "updated-min" on the calendar feed, I get results containing events that have changed, but these results don't include events with new comments.

So this leads me to believe I would have query every single event's comment feed to determine if any new comments have been added - which is painfully inefficient. It would be nice if a calendar query also reported events who's comment feed were updated, saving us the cost of querying events without new comments.

I do, however, like the idea of having a separate feed for comments - it's like a Kinder surprise with smaller and smaller eggs :)

Likewise, if you enable multiple calendars in future API releases, it would be nice if there were a top level query that would inform us of which calendar feeds have changed, saving us the cost of querying each calendar.

From one client call we could know exactly what calendars were changed, what events were changed, and if any new comments were added to an event. That would be cool!