date = smalldatetime
The ability to equate a date field with a smalldatetime field that has "00:00:00" for the time. Ex: '2014-01-01' is equal to '2014-01-01 00:00:00' in most scenarios. These are considered different dates as of 10.4.8.62 of SQL Data Compare.
Mike Chabot commented
When I try to compare a datetime with a date I sometimes see this error: Unable to compare between fields as_of_date and as_of_date, types being compared System.DateTime and System.String. So SQL Data Compare is treating the field of type = date as a string when doing the comparison.