Not what I thought I was buying...

You should evaluate the Lite version first to be sure this app works as you think. I failed to do so.
Events that you enter on the calendar sync as expected.
ToDo items or Tasks do not sync across devices. Making this little better than the iCalendar app which is free.
When I hear back from their support people, I will revisit this review, but until then...
Update: their support people confirm that ToDo items do not sync across devices.
Caveat Emptor.

HeadMoose about Task and Cal : Easily Manage your Tasks and Calendar