Not much difference. I won't buy a pistol with the 80s guts and the price is comparable between the two.
You can remove the Series 80 guts and place a $5 shim in the receiver to get rid of the firing pin jackassery. This will clean up the trigger break and relieve you of the patchwork of shit that can malfunction and prevent the pistol from firing.
http://www.brownells.com/.aspx/pid=1...ME_SLOT_BLANK#