Essentially what the Advanced Mirror will do is act as a sort of medium between Mirror Geometry and Duplicate Special, with some added features.
As expected, there's selections for mirroring across any of the three axis, positive or negative. The next section is where the nice bits come in. Under Mirror Location the user can select where it is the mirrored copy of the object will be placed once it has been created. The object can be set to be placed at the origin (0,0,0), flipped across the grid to the opposite side of the origin, adjacent to the object (bounding boxes touching), adjacent but at a distance, at a predetermined locator, or at an exact point provided.
The final two options are for if you want to have the original and mirrored copy combined, and then for if you want the mirrored copy to have its transforms frozen*
To use, simply type advancedMirror in the command line (after loading it into Maya)!
*While you will receive a warning notice that the opposite node will be applied, I have taken this into consideration and the Mel script fixes this. So just ignore that warning and check for yourself: the opposite node will not be applied!!!
P.S. Some options will not work for NURBS, such as the combine check box. Try to limit useage to Polygonal meshes!
P.P.S PLEASE give me feedback for extra features or how well the program works for you in the review section!
-Benjamin Taylor Winn