I used it in the D-league and had some good results. Then when I joined a team my owner had me keep it off until the last 3 games of the season. Since I have used it my Passer rating has sky rocketed, the number of drops and PD's have fallen dramatically.
Sure if it is exactly due to turning on Favor Long Pass, and my team is still debating whether I should keep it on or not. Something tells me there gonna vote to turn it off.
Check the stat change from games 1-13 to 14-16:
http://goallineblitz.com/game/player_game_log.pl?player_id=606941