dialog appears when you right click after a selection.

If you have ever been annoyed by where it opts to appear, you can now set it to appear relative to your cursor or float.

 

You can modify the setting by right clicking right on the Quick Properties dialog and select Settings from the right click menu.

 

When I create an array in AutoCAD, I always hit the Preview button...this is my little sanity check that saves me from doing an undo if I messed up on my settings.

 

In prior releases, when the preview came up you got a small dialog with buttons that said Accept, Modify, Cancel.  In 2009, if you blink you'll miss the prompt...click your left mouse button to accept the previewed array or click the right mouse button to return to the dialog.  I was looking all over for the accept/modify/cancel buttons and forgot to look down at my command line for instructions.  Once I understood, I liked the new option...but it definitely sneaks up on veteran users.