What is the difference between "all unplayed" and "all new" podcasts?
If you have three podcasts as follows:


A - downloaded, synced and played
B - downloaded, synced and not played
C - newly downloaded, never synced, and not played


When choosing "all unplayed", podcasts B &amp; C will by synced. A will be removed from the iDevice

When choosing "all new", only C will be synced.  A &amp; B will be removed from the iDevice