I've used it in 3 leagues. Gotten positive feedback on it. A loss is 0. A win gets them 3 points plus additional points based on how much they won their NFL game by. One league gives an additional 1/2 point per NFL score differential, the other 2 give 1/3 point.
So in the higher scoring league, if your coach's team wins by 10 you get 3 for the win and then get 5 more for the 10 point differential for a total of 8. If he wins by 30 you would get 17. If he loses you get a 0. In the 1/3 point league the 30 point win would get you 13 fantasy points.
In either league, the coach averages are well below the offensive player averages both in total points and in VBD value. Even a rare 30 point blowout win only nets you as much as a RB with a TD and 70 total yards.
But which team will beat which is something people can use skill in trying to predict, so I think it adds to the game.
Oh, and if you use MFL, I suggest you do this with the "Offense" category instead of the "Head Coach" category. The Head Coach treats the coach as an individual guy... so when Martz was in the hospital, you wouldn't get points for the Rams results unless you picked up Joe Vitte. If you want to go that route then do use Head Coach, but we wanted it to be drafting the head coach of a team and always having that team, so we switched to using Offense.