I was playing COD4 in a friendly fire server when the map Downpour was in queue. Normally, in a regular server, I would leave immediately. Downpour is by far the most unbalanced map in the game (Creek is the worst, IW made an unbalanced map from scratch).
But with friendly fire on and a script that temporarily banishes frequent team killers, I found the round quite pleasant.
All the sudden, nobody is throwing grenades at random. No is abusing the stationary machine gun. People “try” to hold their fire when they see teammates in front of them. The server also cut the HP of the chopper, which enhances the experience even more.
Sure, occasionally I get the urge to execute a teammate because he is block my shot. But overall, it raises the discipline of each player when FF is used.
Of course, viability of FF depends on how servers deal with intentional TK’s. Otherwise, I consider FF to be better than Hardcore mode for realistic shooters.
Note: This is the server’s homepage.