Yes, IRIS becomes better and better and is much underrated in our comunity, I think. I presume a CALENDAR-function will be added in a future release - that's a big point for me.
What I miss, is the possibility to drag&drop mails outside of IRIS to a certain place (directory) and to put it back the same way (as outlook can do). This will help a lot in quick managing emails. At moment there is only a menue-function for importing mails (.eml , which works great with YAM or outlook, btw.), bot nothing to export in .eml-format.