The difference between the Active Filter and is Active object in results is as follows:
Active filter - Applying this object will take into account any other filters being applied. Use of this object will allow you to determine active participants within an additional program filter. This filter will automatically prompt you for a date range.
'Is Active' object - The Is Active object will give you a 'Yes' or 'No' value. This filter is not program specific. If you apply this filter it will not take into account whether you are also filtering for programs, it will just tell you whether or not the subject(s) is/are active anywhere in your enterprise.