I might have skipped TouchDown at the time, because 1) it does not integrate with the native calendar and contacts (or at least the screenshots imply that it is

I might have skipped TouchDown at the time, because 1) it does not integrate with the native calendar and contacts (or at least the screenshots imply that it is a built-in functionality), 2) it looks like from Gingerbread era, 3) has separate versions for phone and tablet. Nine had neither of these issues.