I just turned FO late last year and took a MR on Delta last November that
went MCI-ATL-STL-ATL-LAX_ATL-CVG-MCI. I was able to get upgraded on all segments but two...STL-ATL and ATL-CVG. Thats a nice 71% success rate for upgrades as a FO on this particular trip. Granted , I did travel on a Saturday when most of the business travelers are at home and my LAX-ATL flight was a red-eye. Im sure these factors helped a little.

What is your experience with upgrades as an FO? So far, everything has been pretty good for me. ^