I'm using franchise, and I'm currently using a tweaked version of Big Ant's sliders.
The games are very realistic seeing as I'm using my sorry Jets. For example, I played Jacksonville last night. Uptil the fourth quarter, It's a tight 10-6 game in my favor, Bollinger is managing the game, and my run game is some what productive. The defense gives up a field goal after a long drive. Bollinger throws up a pick after that, and my tired defense can't seem to tackle Fred Taylor. Bollinger continues to throw picks, Taylor continues to own me. Great stuff. I just wish there were real draft classes.
The key is strafing though, it keeps you from getting sucked up sometimes, but not all the time. And you need a quick MLB. You really can't sit back and diagnose the play, you have to find where the HB is going and shoot the gap. Not exactly the most realistic way of playing LB, but it's better than nothing.
Hope that helps.